opinion: Mr. Chief Justice Warren
  delivered the opinion of the Court.
  These cases involve the validity of certain Rules of Procedure adopted by the Commission on Civil Rights, which was established by Congress in 1957. Civil Rights Act of 1957, 71 Stat. 634, 42 U. S. C. §§ 1975-1975e. They arise out of the Commission’s investigation of alleged Negro voting deprivations in the State of Louisiana. The appellees in No. 549 are registrars of voters in the State of Louisiana, and the respondents in No. 550 are private citizens of Louisiana. After having been summoned to appear before a hearing which the Commission proposed to conduct in Shreveport, Louisiana, these registrars and private citizens requested the United States District Court for the Western District of Louisiana to enjoin the Commission from holding its anticipated hearing. It was alleged, among other things, that the Commission’s Rules of Procedure governing the conduct of its investigations were unconstitutional. The specific rules challenged are those which provide that the identity of persons submitting complaints to the Commission need not be disclosed, and that those summoned to testify before the Commission, including persons against whom complaints have been filed, may not cross-examine other witnesses called by the Commission. The District Court held that the Commission was not authorized to adopt the Rules of Procedure here in question, and therefore issued an injunction which prohibits the Commission from holding any hearings in the Western District of Louisiana as long as the challenged procedures remain in force. The Commission requested this Court to review the District Court’s decision. We granted the Commission’s motion to advance the cases, and oral argument was accordingly scheduled on the jurisdiction on appeal in No. 549, on the petition for certiorari in No. 550, and on the merits of both cases.
  Having heard oral argument as scheduled, we now take jurisdiction in No. 549 and grant certiorari in No. 550. The specific questions which we must decide are (1) whether the Commission was authorized by Congress to adopt the Rules of Procedure challenged by the respondents, and (2) if so, whether those procedures violate the Due Process Clause of the Fifth Amendment.
  A description of the events leading up to this litigation is necessary not only to place the legal questions in their proper factual context, but also to indicate the significance of the Commission’s proposed Shreveport hearing. During the months prior to its decision to convene the hearing, the Commission had received some sixty-seven complaints from individual Negroes who alleged that they had been discriminatorily deprived of their right to vote. Based upon these complaints, and pursuant to its statutory mandate to “investigate allegations in writing under oath or affirmation that certain citizens of the United States are being deprived of their right to vote and have that vote counted by reason of their color, race, religion, or national origin,” the Commission began its investigation into the Louisiana voting situation by making several ex parte attempts to acquire information. Thus, in March 1959, a member of the Commission’s staff interviewed the Voting Registrars of Claiborne, Caddo, and Webster Parishes, but obtained little relevant information. During one of these interviews the staff member is alleged to have informed Mrs. Lannie Linton, the Registrar of Claiborne Parish, that the Commission had on file four sworn statements charging her with depriving Negroes of their voting rights solely because of their race. Subsequent to this interview, Mr. W. M. Shaw, Mrs. Linton’s personal attorney, wrote a letter to Mr. Gordon M. Tiffany, the Staff Director of the Commission, in which it was asserted that Mrs. Linton knew the sworn complaints lodged against her to be false. The letter also indicated that Mrs. Linton wished to prefer perjury charges against the affiants, and Mr. Shaw therefore demanded that the Commission forward to him copies of the affidavits so that a proper presentment could be made to the grand jury. On April 14, 1959, Mr. Tiffany replied to Mr. Shaw’s letter and indicated that the Commission had denied the request for copies of the sworn affidavits. Mr. Shaw was also informed of the following official statement adopted by the Commission:
  “The Commission from its first meeting forward, having considered all complaints submitted to it as confidential because such confidentiality is essential in carrying out the statutory duties of the Commission, the Staff Director is hereby instructed not to disclose the names of complainants or other information contained in complaints to anyone except members of the Commission and members of the staff assigned to process, study, or investigate such complaints.”
  A copy of Mr. Tiffany’s letter was sent to Mr. Jack P. F. Gremillion, the Attorney General of Louisiana, who had previously informed the Commission that under Louisiana law the Attorney General is the legal adviser for all voting registrars in any hearing or investigation before a federal commission.
  Another attempt to obtain information occurred on May 13, 1959, when Mr. Tiffany, upon Commission authorization, sent a list of 315 written interrogatories to Mr. Gremillion. These interrogatories requested very detailed and specific information, and were to be answered by the voting registrars of nineteen Louisiana parishes. Although Mr. Gremillion and the Governor of Louisiana had previously assented to the idea of written interrogatories, on May 28, 1959, Mr. Gremillion sent a letter to Mr. Tiffany indicating that the voting registrars refused to answer the interrogatories. The reasons given for the refusal were that many of the questions seemed unrelated to the functions of voting registrars, that the questions were neither accompanied by specific complaints nor related to specific complaints, and that the time and research required to answer the questions placed an unreasonable burden upon the voting registrars.
  In response to this refusal, on May 29,1959, Mr. Tiffany sent a telegram to Mr. Gremillion, informing the latter that the interrogatories were based upon specific allegations received by the Commission, and reaffirming the Commission’s position that the identity of specific complainants would not be disclosed. Mr. Tiffany’s letter contained a further request that the interrogatories be answered and sent to the Commission by June 5, 1959. On June 2, 1959, Mr. Gremillion wrote a letter to Mr. Tiffany reiterating the registrars’ refusal, and again. requesting that the names of complainants be disclosed.
  Finally, as a result of this exchange of correspondence, and because the Commission’s attempts to obtain information ex parte had been frustrated, the Commission, acting pursuant to Section 105 (f) of the Civil Rights Act of 1957, decided to hold the Shreveport hearing commencing on July 13, 1959.
  Notice of the scheduled hearing was sent to Mr. Gremil-lion, and between June 29 and July 6, subpoenas duces tecum were served on the respondents in No. 549, ordering them to appear at the hearing and to bring with them various voting and registration records within their custody and control. Subpoenas were also served upon the respondents in No. 550. These private citizens were apparently summoned to explain their activities with regard to alleged deprivations of Negro voting rights.
  On July 8, 1959, Mr. Tiffany wrote to Mr. Gremillion, enclosing copies of the Civil Rights Act and of the Commission’s Rules of Procedure. Mr. Gremillion’s attention was also drawn to Section 102 (h) of the Civil Rights Act, which permits witnesses to submit, subject to the discretion of the Commission, brief and pertinent sworn statements for inclusion in the record.
  Two days later, on July 10, 1959, the respondents in No. 549 and No. 550 filed two separate complaints in the District Court for the Western District of Louisiana. Both complaints alleged that the respondents would suffer irreparable harm by virtue of the Commission’s refusal to furnish the names of persons who had filed allegations of voting deprivations, as well as the contents of the allegations, and by its further refusal to permit the respondents to confront and cross-examine the persons making such allegations. In addition, both complaints alleged that the Commission’s refusals not only violated numerous provisions of the Federal Constitution, but also constituted “ultra vires” acts not authorized either by Congress or the Chief Executive. The respondents in No. 549 also alleged that they could not comply with the subpoenas duces tecum because Louisiana law prohibited voting registrars from removing their voting records except “upon an order of a competent court,” and because the Commission was not such a “court.” Finally, the complaint in No. 549 alleged that the Civil Rights Act was unconstitutional because it did not constitute “appropriate legislation within the meaning of Section (2) of the XY Amendment.”
  Both complaints sought a temporary restraining order and a permanent injunction prohibiting the members of the Commission (a) from compelling the “testimony from or the production of any records” by the respondents until copies of the sworn charges, together with the names and addresses of the persons filing such charges were given to the respondents; (b) from “conducting any hearing pursuant to the rules and regulations adopted by” the Commission; and (c) from “conspiring together ... or with any other person ... to deny complainants their rights and privileges as citizens” of Louisiana or the United States “or to deny to complainants their right to be confronted by their accusers, to know the nature and character of the charges made against them,” and to be represented by counsel. The complaint in No. 549 also sought a declaratory judgment that the Civil Rights Act of 1957 was unconstitutional.
  On the day that the complaints were filed, the district judge held a combined hearing on the prayers for temporary restraining orders. On July 12, 1959, he found that the respondents would suffer irreparable harm if the hearings were held as scheduled, and he therefore issued the requested temporary restraining orders and rules to show cause why a preliminary injunction should not be granted. Larche v. Hannah, 176 F. Supp. 791. The order prohibited the Commission from holding any hearings which concerned the respondents or others similarly situated until a determination was made on the motion for a preliminary injunction.
  Inasmuch as the complaint in No. 549 attacked the constitutionality of the Civil Rights Act, a three-judge court was convened pursuant to 28 U. S. C. § 2282. Since the complaint in No. 550 did not challenge the constitutionality of the Civil Rights Act of 1957, that case was scheduled to be heard by a single district judge. That district judge was also a member of the three-judge panel in No. 549, and a combined hearing was therefore held on both cases on August 7, 1959.
  On October 7,1959, a divided three-judge District Court filed an opinion in No. 549. Larche v. Hannah, 177 F. Supp. 816. The court held that the Civil Rights Act of 1957 was constitutional since it “very definitely constitutes appropriate legislation” authorized by the Fourteenth and Fifteenth Amendments and Article I, Section 2, of the Federal Constitution. Id., at 821. The court then held that since the respondents’ allegations with regard to apprisal, confrontation, and cross-examination raised a “serious constitutional issue,” this Court’s decision in Greene v. McElroy, 360 U. S. 474, required a preliminary determination as to whether Congress specifically authorized the Commission “to adopt rules for investigations . . . which would deprive parties investigated of their rights of confrontation and cross-examination and their right to be apprised of the charges against them.” 177 F. Supp., at 822. The court found that Congress had not so authorized the Commission, and an injunction was therefore issued. In deciding the case on the issue of authorization, the court never reached the “serious constitutional issue” raised by the respondents’ allegations. The injunction prohibits the Commission from holding any hearing in the Western District of Louisiana wherein the registrars, “accused of depriving others of the right to vote, would be denied the right of apprisal, confrontation, and cross examination.” The single district judge rendered a decision in No. 550 incorporating by reference the opinion of the three-judge District Court, and an injunction, identical in substance to that entered in No. 549, was issued.
  I.
  We held last Term in Greene v. McElroy, supra, that when action taken by an inferior governmental agency was accomplished by procedures which raise serious constitutional questions, an initial inquiry will be made to determine whether or not “the President or Congress, within their respective constitutional powers, specifically has decided that the imposed procedures are necessary and warranted and has authorized their use.” Id., at 507. The considerations which prompted us in Greene to analyze the question of authorization before reaching the constitutional issues presented are no less pertinent in this case. Obviously, if the Civil Rights Commission was not authorized to adopt the procedures complained of by the respondents, the case could be disposed of without a premature determination of serious constitutional questions. See Vitarelli v. Seaton, 359 U. S. 535; Kent v. Dulles, 357 U. S. 116; Watkins v. United States, 354 U. S. 178; Peters v. Hobby, 349 U. S. 331.
  We therefore consider first the question of authorization. As indicated above, the Commission specifically refused to disclose to the respondents the identity of persons who had submitted sworn complaints to the Commission and the specific charges contained in those complaints. Moreover, the respondents were informed by the Commission that they would not be permitted to cross-examine any witnesses at the hearing. The respondents contend, and the court below held, that Congress did not authorize the adoption of procedural rules which would deprive those being investigated by the Commission of the rights to apprisal, confrontation, and cross-examination. The court’s holding is best summarized by the following language from its opinion:
  “[W]e find nothing in the Act which expressly authorizes or permits the Commission’s refusal to inform persons, under investigation for criminal conduct, of the nature, cause and source of the accusations against them, and there is nothing in the Act authorizing the Commission to deprive these persons of the right of confrontation and cross-examination.” 177 F. Supp., at 822.
  After thoroughly analyzing the Rules of Procedure contained in the Civil Rights Act of 1957 and the legislative history which led to the adoption of that Act, we are of the opinion that the court below erred in its conclusion and that Congress did authorize the Commission to adopt the procedures here in question.
  It could not be said that Congress ignored the procedures which the Commission was to follow in conducting its hearings. Section 102 of the Civil Rights Act of 1957 lists a number of procedural rights intended to safeguard witnesses from potential abuses. Briefly summarized, the relevant subdivisions of Section 102 provide that the Chairman shall make an opening statement as to the subject of the hearing; that a copy of the Commission’s rules shall be made available to witnesses; that witnesses “may be accompanied by their own counsel for the purpose of advising them concerning their constitutional rights”; that potentially defamatory, degrading, or incriminating testimony shall be received in executive session, and that any person defamed, degraded, or incriminated by such testimony shall have an opportunity to appear voluntarily as a witness and to request the Commission to subpoena additional witnesses; that testimony taken in executive session shall be released only upon the consent of the Commission; and that witnesses may submit brief and pertinent sworn statements in writing for inclusion in the record.
  The absence of any reference to apprisal, confrontation, and cross-examination, in addition to the fact that counsel’s role is specifically limited to advising witnesses of their constitutional rights, creates a presumption that Congress did not intend witnesses appearing before the Commission to have the rights claimed by respondents. This initial presumption is strengthened beyond any reasonable doubt by an investigation of the legislative history of the Act.
  • The complete story of the 1957 Act begins with the 1956 House Civil Rights Bill, H. R. 627. That bill was reported out of the House Judiciary Committee without any reference to the procedures to be used by the Commission in conducting its hearings. H. R. Rep. No. 2187, 84th Cong., 2d Sess. During the floor debate, Representative Dies of Texas introduced extensive amendments designed to regulate the procedure of Commission hearings. 102 Cong. Rec. 13542. Those amendments would have guaranteed to witnesses appearing before the Commission all of the rights claimed by the respondents in these cases. The amendments provided, in pertinent part, that a person who might be adversely affected by the testimony of another “shall be fully advised by the Commission as to the matters into which the Commission proposes to inquire and the adverse material which is proposed to be presented”; that a person adversely affected by evidence or testimony given at a public hearing could “appear and testify or file a sworn statement in his own behalf”; that such a person could also “have the adverse witness recalled” within a stated time; and that he or his counsel could cross-examine adverse witnesses.
  The bill, as finally passed by the House, contained all of the amendments proposed by Representative Dies. 102 Cong. Rec. 13998-13999. However, before further action could be taken, the bill died in the Senate. Although many proposals relating to civil rights were introduced in the 1957 Session of Congress, two bills became the prominent contenders for support. One was S. 83, a bill introduced by Senator Dirksen containing the same procedural provisions that the amended House bill in 1956 had contained. The other bill, H. R. 6127, was introduced by Representative Celler, Chairman of the House Judiciary Committee, and this bill incorporated the so-called House “fair play” rules as the procedures which should govern the conduct of Commission hearings. After extensive debate and hearings, H. R. 6127 was finally passed by both Houses of Congress, and the House “fair play” rules, which make no provision for advance notice, confrontation, or cross-examination, were adopted in preference to the more protective rules suggested in S. 83.
  The legislative background of the Civil Rights Act not only provides evidence of congressional authorization, but it also distinguishes these cases from Greene v. McElroy, supra, upon which the court below relied so heavily. In Greene there was no express authorization by Congress or the President for the Department of Defense to adopt the type of security clearance program there involved. Nor was there any legislative history or executive directive indicating that the Secretary of Defense was authorized to establish a security clearance program which could deprive a person of his government employment on the basis of secret and undisclosed information. Therefore, we concluded in Greene that because of the serious constitutional problems presented, mere acquiescence by the President or the Congress would not be sufficient to constitute authorization for the security clearance procedures adopted by the Secretary of Defense. The facts of this case present a sharp contrast to those before the Court in Oreene. Here, we have substantially more than the mere acquiescence upon which the Government relied in Oreene. There was a conscious, intentional selection by Congress of one bill, providing for none of the procedures demanded by respondents, over another bill, which provided for all of those procedures. We have no doubt that Congress’ consideration and rejection of the procedures here at issue constituted an authorization to the Commission to conduct its hearings according to the Rules of Procedure it has adopted, and to deny to witnesses the rights of apprisal, confrontation, and cross-examination.
  II
  The existence of authorization inevitably requires us to determine whether the Commission’s Rules of Procedure are consistent with the Due Process Clause of the Fifth Amendment.
  Since the requirements of due process frequently vary with the type of proceeding involved, e. g., compare Opp Cotton Mills, Inc. v. Administrator, 312 U. S. 126, 152, with Interstate Commerce Comm’n v. Louisville & N. R. Co., 227 U. S. 88, 91, we think it is necessary at the outset to ascertain both the nature and function of this Commission. Section 104 of the Civil Rights Act of 1957 specifies the duties to be performed by the Commission. Those duties consist of (1) investigating written, sworn allegations that anyone has been discriminatorily deprived of his right to vote; (2) studying and collecting information “concerning legal developments constituting a denial of equal protection of the laws under the Constitution”; and (3) reporting to the President and Congress on its activities, findings, and recommendations. As is apparent from this brief sketch of the statutory duties imposed upon the Commission, its function is purely investigative and fact-finding. It does not adjudicate. It does not hold trials or determine anyone’s civil or criminal liability. It does not issue orders. Nor does it indict, punish, or impose any legal sanctions. It does not make determinations depriving anyone of his life, liberty, or property. In short, the Commission does not and cannot take any affirmative action which will affect an individual’s legal rights. The only purpose of its existence is to find facts which may subsequently be used as the basis for legislative or executive action.
  The specific constitutional question, therefore, is whether persons whose conduct is under investigation by a governmental agency of this nature are entitled, by virtue of the Due Process Clause, to know the specific charges that are being investigated, as well as the identity of the complainants, and to have the right to cross-examine those complainants and other witnesses. Although these procedures are very desirable in some situations, for the reasons which we shall now indicate, we are of the opinion that they are not constitutionally required in the proceedings of this Commission.
  “Due process” is an elusive concept. Its exact boundaries are undefinable, and its content varies according to specific factual contexts. Thus, when governmental agencies adjudicate or make binding determinations which directly affect the legal rights of individuals, it is imperative that those agencies use the procedures which have traditionally been associated with the judicial process. On the other hand, when governmental action does not partake of an adjudication, as for example, when a general fact-finding investigation is being conducted, it is not necessary that the full panoply of judicial procedures be used. Therefore, as a generalization, it can be said that due process embodies the differing rules of fair play, which through the years, have become associated with differing types of proceedings. Whether the Constitution requires that a particular right obtain in a specific proceeding depends upon a complexity of factors. The nature of the alleged right involved, the nature of the proceeding, and the possible burden on that proceeding, are all considerations which must be taken into account. An analysis of these factors demonstrates why it is that the particular rights claimed by the respondents need not be conferred upon those appearing before purely investigative agencies, of which the Commission on Civil Rights is one.
  It is probably sufficient merely to indicate that the rights claimed by respondents are normally associated only with adjudicatory proceedings, and that since the Commission does not adjudicate, it need not be bound by adjudicatory procedures. Yet, the respondents contend, and the court below implied, that such procedures are required since the Commission's proceedings might"' irreparably harm those being investigated by subjecting them to public opprobrium and scorn, the distinct likelihood of losing their jobs, and the possibility of criminal prosecutions. That any of these consequences will result is purely conjectural. There is nothing in the record to indicate that such will be the case or that past Commission hearings have had any harmful effects upon witnesses appearing before the Commission. However, even if such collateral consequences were to flow from the Commission’s investigations, they would not be the result of any affirmative determinations made by the Commission, and they would not affect the legitimacy of the Commission's investigative function.
  On the other hand, the investigative process could be completely disrupted if investigative hearings were transformed into trial-like proceedings, and if persons who might be indirectly affected by an investigation were given an absolute right to cross-examine every witness called to testify. Fact-finding agencies without any power to adjudicate would be diverted from their legitimate duties and would be plagued by the injection of collateral issues that would make the investigation interminable. Even a person not called as a witness could demand the right to appear at the hearing, cross-examine any witness whose testimony or sworn affidavit allegedly defamed or incriminated him, and call an unlimited number of witnesses of his own selection. This type of proceeding would make a shambles of the investigation and stifle the agency in its gathering of facts.
  In addition to these persuasive considerations, we fhink it is highly significant that the Commission’s procedures are not historically foreign to other forms of investigation under our system. Far from being unique, the Rules of Procedure adopted by the Commission are similar to those which, as shown by the Appendix to this opinion, have traditionally governed the proceedings of the vast majority of governmental investigating agencies.
  A frequently used type of investigative agency is the legislative committee. The investigative function of such committees is as old as the Republic. The volumes written about legislative investigations have ¡proliferated almost as rapidly as the legislative committees themselves, and the courts have on more than one occasion been confronted with the legal problems presented by such committees. The procedures adopted by legislative investigating committees have varied over the course of years. Yet, the history of these committees clearly demonstrates that only infrequently have witnesses appearing before congressional committees been afforded the procedural rights normally associated with an adjudicative proceeding. In. the vast majority of instances, congressional committees have not given witnesses detailed notice or an opportunity to confront, cross-examine and call other witnesses.
  The history of investigations conducted by the executive branch of the Government is also marked by a decided absence of those procedures here in issue. The best example is provided by the administrative regulatory agencies. Although these agencies normally make determinations of a quasi-judicial nature, they also frequently conduct purely fact-finding investigations. When doing the former, they are governed by the Administrative Procedure Act, 60 Stat. 237, 5 U. S. C. §§ 1001-1011, and the parties to the adjudication are accorded the traditional safeguards of a trial. However, when these agencies are conducting nonadjudicative, fact-finding investigations, rights such as apprisal, confrontation, and cross-examination generally do not obtain.
  A typical agency is the Federal Trade Commission. Its rules draw a clear distinction between adjudicative proceedings and investigative proceedings. 16 CFR, 1958 Supp., § 1.34. Although the latter are frequently initiated by complaints from undisclosed informants, id., §§ 1.11, 1.15, and although the Commission may use the information obtained during investigations to initiate adjudicative proceedings, id., § 1.42, nevertheless, persons summoned to appear before investigative proceedings are entitled only to a general notice of “the purpose and scope of the investigation,” id., § 1.33, and while they may have the advice of counsel, “counsel may not, as a matter of right, otherwise participate in the investigation.” Id., § 1.40. The reason for these rules is obvious. The Federal Trade Commission could not conduct an efficient investigation if persons being investigated were permitted to convert the investigation into a trial. We have found no authorities suggesting that the rules governing Federal Trade Commission investigations violate the Constitution, and this is understandable since any person investigated by the Federal Trade Commission will be accorded all the traditional judicial safeguards at a subsequent adjudicative proceeding, just as any person investigated by the Civil Rights Commission will have all of these safeguards, should some type of adjudicative proceeding subsequently be instituted.
  Another regulatory agency which distinguishes between adjudicative and investigative proceedings is the Securities and Exchange Commission. This Commission conducts numerous investigations, many of which are initiated by complaints from private parties. 17 CFR § 202.4. Although the Commission’s Rules provide that parties to adjudicative proceedings shall be given detailed notice of the matters to be determined, id., 1959 Supp., § 201.3, and a right to cross-examine witnesses appearing at the hearing, id., § 201.5, those provisions of the Rules are made specifically inapplicable to investigations, id., § 201.20, even though the Commission is required to initiate civil or criminal proceedings if an investigation discloses violations of law. Undoubtedly, the reason for this distinction is to prevent the sterilization of investigations by burdening them with trial-like procedures.
  Another type of executive agency which frequently conducts investigations is the presidential commission. Although a survey of these commissions presents no definite pattern of practice, each commission has generally been permitted to adopt whatever rules of procedure seem appropriate to it, and it is clear that many of the most famous presidential commissions have adopted rules similar to those governing the proceedings of the Civil Rights Commission. For example, the Roberts Commission established in 1941 to ascertain the facts relating to the Japanese attack upon Pearl Harbor, and to determine whether the success of the attack resulted from any derelictions of duty on the part of American military personnel, did not permit any of the parties involved in the investigation to cross-examine other witnesses. In fact, many of the persons whose conduct was being investigated were not represented by counsel and were not present during the interrogation of other witnesses. Hearings before the Joint Committee on the Investigation of the Pearl Harbor Attack, 79th Cong., 1st Sess., pts. 22-25.
  Having considered the procedures traditionally followed by executive and legislative investigating agencies, we think it would be profitable at this point to discuss the oldest and, perhaps, the best known of all investigative bodies, the grand jury. It has never been considered necessary to grant a witness summoned before the grand jury the right to refuse to testify merely because he did not have access to the identity and testimony of prior witnesses. Nor has it ever been considered essential that a person being investigated by the grand jury be permitted to come before that body and cross-examine witnesses who may have accused him of wrongdoing. Undoubtedly, the procedural rights claimed by the respondents have not been extended to grand jury hearings because of the disruptive influence their injection would have on the proceedings, and also because the grand jury merely investigates and reports. It does not try.
  We think it is fairly clear from this survey of various phases of governmental investigation that witnesses appearing before investigating agencies, whether legislative, executive, or judicial, have generally not been accorded the rights of apprisal, confrontation, or cross-examination. Although we do not suggest that the grand jury and the congressional investigating committee are identical in all respects to the Civil Rights Commission, we mention them, in addition to the executive agencies and commissions created by Congress,, to show that the rules of this Commission are not alien to those which have historically governed the procedure of investigations conducted by agencies in the three major branches of our Government. The logic behind this historical practice was recognized and described by Mr. Justice Cardozo’s landmark opinion in Norwegian Nitrogen Products Co. v. United States, 288 U. S. 294. In that case, the Court was concerned with the type of hearing that the Tariff Commission was required to hold when conducting its investigations. Specifically, the Court was asked to decide whether the Tariff Act of 1922, 42 Stat. 858, gave witnesses appearing before the Commission the right to examine confidential information in the Commission files and to cross-examine other witnesses testifying at Commission hearings. Although the Court did not phrase its holding in terms of due process, we think that the following language from Mr. Justice Cardozo’s opinion is significant:
  “The Tariff Commission advises; these others ordain. There is indeed this common bond that all alike are instruments in a governmental process which according to the accepted classification is legislative, not judicial. . . . Whatever the appropriate label, the kind of order that emerges from a hearing before a body with power to ordain is one that impinges upon legal rights in a very ^different way from the report of a commission which merely investigates and advises. The traditionary forms of hearing appropriate to the one body are unknown to the other. What issues from the Tariff Commission as a report and recommendation to the President, may be accepted, modified, or rejected. If it happens to be accepted, it does not bear fruit in anything that trenches upon legal rights.” 288 U. S., at 318.
  And in referring to the traditional practice of investigating bodies, Mr. Justice Cardozo had this to say:
  “[W]ithin the meaning of this act the “hearing’ assured to one affected by a change of duty does not include a privilege to ransack the records of the Commission, and to subject its confidential agents to an examination as to all that they have learned. There was no thought to revolutionize the practice of investigating bodies generally and of this one in particular.” Id., at 319. (Emphasis supplied.)
  Thus, the purely investigative nature of the Commission’s proceedings, the burden that the claimed rights would place upon those proceedings, and the traditional procedure of investigating'agencies in general, leads us to conclude that the Commission’s Rules of Procedure comport with the requirements of due process.
  Nor do the authorities cited by respondents support their position. They rely primarily upon Morgan v. United States, 304 U. S. 1; Joint Anti-Fascist Refugee Comm. v. McGrath, 341 U. S. 123; and Greene v. McElroy, supra. Those cases are all distinguishable in that the government agency involved in each was found by the Court to have made determinations in the nature of adjudications affecting legal rights. Thus, in Morgan, the action of the Secretary of Agriculture in fixing the maximum rates to be charged by market agencies at stockyards was challenged. In voiding the order of the Secretary for his failure to conduct a trial-like hearing, the Court referred to the adjudicatory nature of the proceeding:
  “Congress, in requiring a 'full hearing,’ had regard to judicial standards, — not in any technical sense but with respect to those fundamental requirements of fairness which are of the essence of due process in a proceeding of a judicial nature.” 304 U. S., at 19.
  Likewise, in Joint Anti-Fascist Refugee Comm. v. McGrath, 341 U. S. 123, 140-141, this Court held that the Attorney General’s action constituted an adjudication. Finally, our decision last year in Greene v. McElroy lends little support to the respondents’ position. The governmental action there reviewed was certainly of a judicial nature. The various Security Clearance Boards involved in Greene were not conducting an investigation; they were determining whether Greene could have a security clearance — a license in a real sense, and one that had a significant impact upon his employment. By contrast, the Civil Rights Commission does not make any binding orders or issue “clearances” or licenses having legal effect. Rather, it investigates and reports leaving affirmative action, if there is to be any, to other governmental agencies where there must be action de novo.
  The respondents have also contended that the Civil Rights Act of 1957 is inappropriate legislation under the Fifteenth Amendment. We have considered this argument, and we find it to be without merit. It would unduly lengthen this opinion to add anything to the District Court’s disposition of this claim. See 177 F. Supp., at 819-821.
  Respondents’ final argument is that the Commission’s hearings should be governed by Section 7 of the Administrative Procedure Act, 60 Stat. 241, 5 U. S. C. § 1006, which specifies the hearing procedures to be used by agencies falling within the coverage of the Act. One of those procedures is the right of every party to conduct “such cross-examination as may be required for a full and true disclosure of the facts.” However, what the respondents fail to recognize is that Section 7, by its terms, applies only to proceedings under Section 4, 60 Stat. 238, 5 U. S. C. § 1003 (rule making), and Section 5, 60 Stat. 239, 5TJ. S. C. § 1004 (adjudications), of the Act. As we have already indicated, the Civil Rights Commission performs none of the functions specified in those sections.
  From what we have said, it is obvious that the District Court erred in both cases in enjoining the Commission from holding its Shreveport hearing. The court's judgments are accordingly reversed, and the cases are remanded with direction to vacate the injunctions.
  Reversed and remanded,
  [For opinion of Mr. Justice Frankfurter, concurring in the result, see post, p. 486.]
  [For concurring opinion of Mr. Justice Harlan, joined by Mr. Justice Clark, see post, p. 493.]
  [For dissenting opinion of Mr. Justice Douglas, joined by Mr. Justice Black, see post, p. 493.]
  Although the Civil Rights Act of 1957 provided that the Commission should cease to exist within two years after its creation, 71 Stat. 635, 42 IT. S. C. § 1975c, in 1959 Congress extended the Commission’s life for an additional two years. 73 Stat. 724.
  The appellants in No. 549 and the petitioners in No. 550 are the individual members of the Civil Rights Commission. Hereinafter,' they will be referred to as “the Commission.” The appellees in No. 549 and the respondents in No. 550 will both hereinafter be referred to as “respondents.”
  Because No. 549 was heard and decided by a three-judge District Court, a direct appeal to this Court was sought by the Commission pursuant to 28 U. S. C. § 1253. The Commission also filed an appeal in No. 550 with the United States Court of Appeals for the Fifth Circuit. However, before the Court of Appeals could render a decision in No. 550, the Commission filed a petition for certiorari pursuant to Rule 20 of this Court.
  Section 104 of the Civil Rights Act of 1957, 71 Stat. 635, 42 U. S. C. § 1975c (a)(1).
  Section 105 (f) of the Civil Rights Act authorizes the Commission to hold hearings and to subpoena witnesses. That section provides:
  "(f) Hearings; issuance of subpeñas.
  “The Commission, or on the authorization of the Commission any subcommittee of two or more members, at least one of whom shall be of each major political party, may, for the purpose of carrying out the provisions of this Act, hold such hearings and act at such times and places as the Commission or such authorized subcommittee may deem advisable. Subpenas for the attendance and testimony of witnesses or the production of written or other matter may be issued in accordance with the rules of the Commission as contained in section 1975a (j) and (k) of this title, over the signature of the Chairman of the Commission or of such subcommittee, and may be served by any person designated by such Chairman.” 71 Stat. 636, 42 ti. S. C. § 1975d (f).
  The role of private citizens in depriving Negroes of their right to vote was one of the questions involved in United States v. McElveen, 180 F. Supp. 10 (E. D. La.), aff’d as to defendant Thomas, 362 U. S. 58.
  Rule 3 (i) of the Commission’s Rules of Procedure, adopted on July 1, 1958, prohibits witnesses or their counsel from cross-examining other witnesses. That Rule reads:
  “Interrogation of witnesses at hearings shall be conducted only by members of the Commission or by authorized staff personnel.”
  The full text of Section 102 (h) of the Civil Rights Act reads as follows:
  “ (h) Submission of written statements.
  “In the discretion of the Commission, witnesses may submit brief and pertinent sworn statements in writing for inclusion in the record. The Commission is the sole judge of the pertinency of testimony and evidence adduced at its hearings.” 71 Stat. 634,42 U. S. C. § 1975a (h).
  Under the Civil Rights Act, the Commission not only has the power to issue subpoenas under Section 105 (f), but, as is customary when Congress confers the subpoena power on an investigative agency, the Commission is also authorized to enforce its subpoenas by enlisting the aid of the federal courts. 71 Stat. 636, 42 U. S. C. § 1975d (g).
  Judge Wisdom, who dissented, was of the opinion that the procedures adopted by the Commission were authorized by Congress, and that those procedures were also constitutional. 177 F. Supp., at 828.
  The court’s injunction reads as follows:
  “For reasons assigned in the Court’s written opinion of October 6, 1959,
  “It is ordered, adjudged and decreed that defendants and their agents, servants, employees and attorneys are enjoined and restrained from conducting the proposed hearing in Shreveport, Louisiana, wherein plaintiff registrars, accused of depriving others of the right to vote, would be denied the right of apprisal, confrontation and cross examination.
  “This injunction does not prohibit all hearings pursuant to Public Law 85-315, 85th Congress, 42 U. S. C. A. 1975, et seq., but only those hearings proposed to be held in the Western District of Louisiana wherein the accused are denied the right of apprisal, confrontation and cross examination.
  “Thus done and signed in Chambers on this the 9 day of November, 1959.”
  The breadth of this injunction is indicated by the fact that the Commission is not only prohibited from compelling respondents’ appearance at the hearing, but it is also enjoined from conducting any hearing in the Western District of Louisiana under existing rules of procedure, whether or not the respondents are called as witnesses.
  The complete text of Section 102 reads as follows:
  “§ 1975a. Rules of 'procedure.
  “(a) Opening statement.
  “The Chairman or one designated by him to act as Chairman at a hearing of the Commission shall announce in an opening statement the subject of the hearing.
  “(b) Copy of rules.
  “A copy of the Commission’s rules shall be made available to the witness before the Commission.
  “(c) Attendance of counsel.
  “Witnesses at the hearings may be accompanied by their own counsel for the purpose of advising them concerning their constitutional rights.
  “(d) Censure and exclusion of counsel.
  “The Chairman or Acting Chairman may punish breaches of order and decorum and unprofessional ethics on the part of counsel, by censure and exclusion from the hearings.
  “(e) Defamatory, degrading or incriminating evidence.
  “If the Commission determines that evidence or testimony at any hearing may tend to defame, degrade, or incriminate any person, it shall (1) receive such evidence or testimony in executive session; (2) afford such person an opportunity voluntarily to appear as a witness; and (3) receive and dispose of requests from such person to subpena additional witnesses.
  “(f) Requests for additional witnesses.
  “Except as provided in this section and section 1975d (f) of this title, the Chairman shall receive and the Commission shall dispose of requests to subpena additional witnesses.
  “(g) Release of evidence taken in executive session.
  “No evidence or testimony taken in executive session may be released or used in public sessions without the consent of the Commission. Whoever, releases or uses in public without the consent of the Commission evidence or testimony taken in executive session shall be fined not more than $1,000, or imprisoned for not more than one year.
  “(h) Submission of written statements.
  “In the discretion of the Commission, witnesses may submit brief and pertinent sworn statements in writing for inclusion in the record. The Commission is the sole judge of the pertinency of testimony and evidence adduced at its hearings.
  “(i) Transcripts.
  “Upon payment of the cost thereof, a witness may obtain a transcript copy of his testimony given at a public session or, if given at an executive session, when authorized by the Commission.
  “(j) Witness fees.
  “A witness attending any session of the Commission shall receive $4 for each day’s attendance and for the time necessarily occupied in going to and returning from the same, and 8 cents per mile for going from and returning to his place of residence. Witnesses who attend at points so far removed from their respective residences as to prohibit return thereto from day to day shall be entitled to an additional allowance of $12 per day for expenses of subsistence, including the time necessarily occupied in going to and returning from the place of attendance. Mileage payments shall be tendered to the witness upon service of a subpena issued on behalf of the Commission or any subcommittee thereof.
  “(k) Restriction on issuance of subpena.
  “The Commission shall not issue any subpena for the attendance and testimony of witnesses or for the production of written or other matter which would require the presence of the party subpenaed at a hearing to be held outside of the State, wherein the witness is found or resides or transacts business.” 71 Stat. 634, 42 U. S. C. § 1975a.
  In addition to the procedural safeguards provided by Section 102 of the Act, the Commission’s Rules of Procedure grant additional protection. Thus, Rule 3 (f) of the Commission’s Rules of Procedure provides:
  “(f) An accurate transcript shall be made of the testimony of all witnesses in all hearings, either public or executive sessions, of the Commission or of any subcommittee thereof. Each witness shall have the right to inspect the record of his own testimony. A transcript copy of his testimony may be purchased by a witness pursuant to Rule 2 (i) above. Transcript copies of public sessions may be obtained by the public upon payment of the cost thereof.”
  And Rule 3 (j) provides:
  “(j) If the Commission pursuant to Rule 2 (e), or any subcommittee thereof, determines that evidence or testimony at any hearing may tend to defame, degrade, or incriminate any person, it shall advise such person that such evidence has been given and it shall afford such person an opportunity to read the pertinent testimony and to appear as a voluntary witness or to file a sworn statement in his behalf.”
  The amendments introduced by Representative Dies read, in pertinent part, as follows:
  “‘(q) A person shall be considered to be adversely affected by evidence or testimony of a witness if the Commission determines that: (i) the evidence or testimony would constitute libel or slander if not presented before the Commission or (ii) the evidence or testimony alleges crime or misconduct or tends to disgrace or otherwise to expose the person to public contempt, hatred, or scorn.
  '“(r) Insofar as practicable, any person whose activities are the subject of investigation by the Commission, or about whom adverse information is proposed to be presented at a public hearing of the Commission, shall be fully advised by the Commission as to the matters into which the Commission proposes to inquire and the adverse material which is proposed to be presented. Insofar as practicable, all material reflecting adversely on the character or reputation of any individual which is proposed to be presented at a public hearing of the Commission shall be first reviewed in executive session to determine its reliability and probative value and shall not be presented at a public hearing except pursuant to majority vote of the Commission.
  “ ‘ (s) If a person is adversely affected by evidence or testimony given in a public hearing, that person shall have the right: (i) to appear and testify or file a sworn statement in his own behalf, (ii) to have the adverse witness recalled upon application made within thirty days after introduction of such evidence or determination of the adverse witness’ testimony, (iii) to be represented by counsel as heretofore provided, (iv) to cross-examine (in person or by counsel) such adverse witness, and (v) subject to the discretion of the Commission, to obtain the issuance by the Commission of subpenas for witnesses, documents, and other evidence in his defense. Such opportunity for rebuttal shall be afforded promptly and, so far as practicable, such hearing shall be conducted at the same place and under the same circumstances as the hearing at which adverse testimony was presented.
  “ 'Cross-examination shall be limited to one hour for each witness, unless the Commission by majority vote extends the time for each witness or group of witnesses.
  “'(t) If a person is adversely affected by evidence or testimony given in executive session or by material in the Commission files or records, and if public release of such evidence, testimony, or material is contemplated such person shall have, prior to the public release of such evidence or testimony or' material or any disclosure of or comment upon it by members of the Commission or Commission staff or taking of similar evidence or testimony in a public hearing, the rights heretofore conferred and the right to inspect at least as much of the evidence or testimony of the adverse witness or material as will be made public or thé subject of a public hearing.
  ‘“(u) Any witness (except a member of the press who testifies in his professional capacity) who gives testimony before the Commission in an open hearing which reflects adversely on the character or reputation of another person may be required by the Commission to disclose his sources of information, unless to do so would endanger the national security.’ ” 102 Cong. Rec. 13542-13543.
  The complete text of the House “fair play” rules may be found in H. Res. 151, 84th Cong., 1st Sess.
  That Congress focused upon the issues here involved and recognized the distinctions between H. R. 6127 and S. 83 is attested to by the following extracts from the floor debate and committee hearings:
  In testifying before both the House and Senate Subcommittees considering the various proposed civil rights bills, Attorney General Brownell supported the adoption of the House “fair play” rules instead of the more restrictive procedures outlined in S. 83. Thus, at the Senate hearings, the Attorney General made the following statement:
  “Now there is one other addition to S. 83 that I would like to make special reference to and that is the provision for rules of procedure contained in section 102 on pages 2 to 10 of S. 83.
  “These rules of procedure are considerably more restrictive than those imposed on regular committees of the House and Senate. There is much in them which clearly would be desirable. We have not as yet had any experience with the use of rules such as those proposed here and we cannot predict the extent to which they might be used to obstruct the work of the Commission.
  “Yet I feel that the task to be given to this Commission is of such great public importance that it would be a mistake to make it the vehicle for experimenting with new rules which may have to be tested out under the courts and this is only a 2-year Commission and you might have to spend those 2 years studying the rules instead of getting at the facts.” Hearings before Subcommittee on Constitutional Rights of the Senate Judiciary Committee, 85th Cong., 1st Sess. 14-15.
  See also Hearings before Subcommittee No. 5 of the House Judiciary Committee, 85th Cong., 1st Sess. 593.
  The lack of any right to cross-examine witnesses was commented upon by members of both the House and the Senate:
  Statement of Senator Talmadge during the Senate floor debate, 103 Cong. Rec. 11504:
  “No provision is made for notification of persons against whom charges are to be made.
  “No provision is made for persons adversely affected by testimony taken by the Commission to be present when they are accused or later to confront and cross-examine their accusers.”
  Statement of 'Senator Stennis during Senate floor debate, 103 Cong. Rec. 13835:
  “Defamatory testimony tending to defame, degrade, or incriminate any person cannot be heard by the person slandered, since the testimony must be taken in executive session. There is no requirement in the proposed statute that the person injured by defamatory testimony shall have an opportunity to examine the nature of the adverse testimony. He has no right of confrontation nor cross-examination, and his request to subpena witnesses on his behalf falls within the arbitrary discretion of the Commission. There is no right to subpena witnesses.”
  Statement of Representative Kilday during House floor debate, 103 Cong. Rec. 8673:
  “The bill provides that witnesses may be accompanied by counsel, for what purpose? Tor the purpose of advising them concerning their constitutional rights.’ That is all. Even though the Commission or its own counsel develops only a portion of a transaction, and that adverse to the witness,' his lawyer cannot ask a single question to develop the remainder of the transaction or the portion favorable to him.”
  Statement of Representative Frazier during Hearings before the House Rules Committee, 85th Cong., 1st Sess. 176:
  “The authors of this proposal contemplate that it will yield thousands of complaints and even more thousands of subpenas will be issued. The various allegations will, in the first instance, be incontrovertible and wholly ex parte and the principal concerned, against whom the charges are made, when summoned as a witness is given no opportunity to cross-examine. True, the person summoned as a witness may have counsel (sec. 102), but only for the purpose of advising him of his constitutional rights.”
  That the bill contained the House “fair play” rules is demonstrated by the following statement of Representative Celler, the author of the bill:
  “The rules of procedure of the Commission are the same as those which govern the committees of the House. For example, the chairman is required to make an opening statement as to the subject of the hearing. Witnesses are furnished with a copy of the Commission’s rules and may be accompanied by counsel. The chairman is authorized to punish breaches of order by censure and exclusion. Protection is furnished to witnesses when it appears that a person may be the subject of derogatory information by requiring such evidence to be received in executive session, and affording the person affected the right to appear and testify, and further to submit a request for subpena of additional witnesses.” 103 Cong. Rec. 8491, (Emphasis supplied.)
  Although the respondents contend that the procedures adopted by the Commission also violate their rights under the Sixth Amendment, their claim does not merit extensive discussion. That Amendment is specifically limited to “criminal prosecutions,” and the proceedings of the Commission clearly do not fall within that category. See United States v. Zucker, 161 U. S. 475, 481.
  The full text of Section 104 of the Act reads as follows:
  “§ 1975c. Duties; reports; termination.
  “(a) The Commission shall—
  “(1) investigate allegations in writing under oath or affirmation that certain citizens of the United States are being deprived of their right to vote and have that vote counted by reason of their color, race, religion, or national origin; which writing, under oath or affirmation, shall set forth the facts upon which such belief or beliefs are based;
  “(2) study and collect information concerning legal developments constituting a denial of equal protection of the laws under the Constitution; and
  “(3) appraise the laws and policies of the Federal Government with respect to equal protection of the laws under the Constitution.
  " (b) The Commission shall submit interim reports to the President and to the Congress at such times as either the Commission or the President shall deem desirable, and shall submit to the President and to the Congress a final and comprehensive report of its activities, findings, and recommendations not later than two years from September 9, 1957.
  "(c) Sixty days after the submission of its final report and recommendations the Commission shall cease to exist.” 71 Stat. 635, 42 U. S. C. § 1975c.
  It should be noted that the respondents in these cases did have notice of the general nature of the inquiry. The only information withheld from them was the identity of specific complainants and the exact charges made by those complainants. Because most of the charges related to the denial of individual voting rights, it is apparent that the Commission could not have disclosed the exact charges without also revealing the names of the complainants.
  Cf. Sinclair v. United States, 279 U. S. 263, 295, holding that Congress’ legitimate right to investigate is not affected by the fact that information disclosed at the investigation may also be used in a subsequent criminal prosecution. Cf. also McGrain v. Daugherty, 273 U. S. 135, 179-180, holding that'a regular congressional investigation is not rendered invalid merely because “it might possibly disclose crime or wrongdoing” on the part 'of witnesses summoned to appear at the investigation. Id., at 180.
  The injunction issued by the court below would certainly lead to this result since it prohibits the Commission from conducting any hearing under existing procedure, even though those being investigated are not summoned to testify.
  A compilation of the rules of procedure governing the investigative proceedings of a representative group of administrative and executive agencies, presidential commissions, and congressional committees is set out in the Appendix to this opinion, post, p. 454.
  The first full-fledged congressional investigating committee was established in 1792 to "inquire into the causes of the failure of the late expedition under Major General St. Clair.” 3 Annals of Cong. 493 (1792). The development and use of legislative investigation by the colonial governments is discussed in Eberling, Congressional Investigations, 13-30. The English origin of legislative investigation in this country is discussed in Dimock, Congressional Investigating Committees, 46-56.
  See, e. g., Kilbourn v. Thompson, 103 U. S. 168; McGrain v. Daugherty, 273 U. S. 135; Sinclair v. United States, 279 U. S. 263; Christoffel v. United States, 338 U. S. 84; United States v. Bryan, 339 U. S. 323; United States v. Fleischman, 339 U. S. 349; Watkins v. United States, 354 U. S. 178; Barenblatt v. United States, 360 U. S. 109.
  See Appendix, post, pp. 478-485. See also Dimock, Congressional Investigating Committees, 153; Eberling, Congressional Investigations, 283, 390; McGeary, The Developments of Congressional Investigative Power, 80; Liacos, Rights of Witnesses Before Congressional Committees, 33 B. U. L. Rev. 337,359-361; American Bar Association, Special Committee on Individual Rights as Affected by National Security, Appendix to Report on Congressional Investigations, 67-68.
  The English practice is described in Clokie and Robinson, Royal Commissions of Inquiry; Finer, Congressional Investigations: The British System, 18 U. of Chi. L. Rev. 521; Keeton, Parliamentary Tribunals of Inquiry, in Yol. 12, Current Legal Problems 1959, 12.
  See Appendix, post, pp. 454-471. See also Gellhorn, Federal Administrative Proceedings, 108; Report of the Attorney General’s Committee on Administrative Procedure and the various Monographs written by that Committee.
  The Commission's practice with regard to investigations was described by the Attorney General’s Committee on Administrative Procedure, Monograph, Securities Exchange Commission, 34-41. The following extract is pertinent here:
  “Where formal investigations are utilized as preliminaries to decisive proceedings, the person being investigated is normally not sent a ■notice, which, in any event, is not public. The order for investigation, which includes the notice, is, however, exhibited to any person examined in the course of such investigation who so requests; since ordinarily the investigation will include the examination of the person suspected of violation, he will, thus, have actual notice of the investigation. Since a person may, on the other hand, be wholly unaware of the fact that he is being investigated until his friends who are interviewed so inform him, and since this may sometimes give rise to antagonism and a feeling that the Commission is besmirching him behind his back, no reason is apparent why, simply as a matter of good will, the Commission should not in ordinary cases send a copy of its order for investigation to the person under investigation.
  “The Commission’s Rules of Practice expressly provide that all such rules (governing notice, amendments, objections to evidence, briefs, and the like) are inapplicable to formal investigatory hearings in the absence of express provision to the contrary in the order and with the exception of rule II, which relates to appearance and practice by representatives before the Commission. The testimony given in such investigations is recorded .... In the usual case, witnesses are granted the right to be accompanied by counsel, but the latter’s role is limited simply to advising the witnesses in respect of their right against self-incrimination without claiming the benefits of the immunity clause of the pertinent statute (a right of which the presiding officer is, in any event, instructed to apprise the witnesses) and to making objections to questions which assertedly exceed the scope of the order of investigation.” Id., 37-38. (Emphasis supplied.) See also Loss, Securities Regulation (1951), 1152.
  Loss, Securities Regulation (1951), 1153. See also the statutes cited in the Appendix, post, p. 463.
  Marcy, Presidential Commissions, 97-101.
  See Appendix, post, pp. 472-479.
  However, the courts have on more than one occasion likened investigative agencies of the executive branch of Government to a grand jury. See, e. g., United States v. Morton Salt Co., 338 U. S. 632, 642; Oklahoma Press Pub. Co. v. Walling, 327 U. S. 186, 216; Consolidated Mines of Calif. v. Securities & Exchange Comm’n, 97 F. 2d 704, 708 (C. A. 9th Cir.); Woolley v. United States, 97 F. 2d 258, 262 (C. A. 9th Cir.).
  The Commission cites In re Groban, 352 U. S. 330, and Anonymous v. Baker, 360 U. S. 287, in support of its position. Each of us who participated in those cases adheres to the view to which he subscribed therein. However, because there are significant differences between the Groban and Anonymous cases and the instant litigation, and because the result we reach today is supported by the other considerations analyzed herein, the Court does not find it necessary to discuss either of those cases.
choices: case did not arise on cert or cert not granted federal court conflict federal court conflict and to resolve important or significant question putative conflict conflict between federal court and state court state court conflict federal court confusion or uncertainty state court confusion or uncertainty federal court and state court confusion or uncertainty to resolve important or significant question to resolve question presented no reason given other reason