opinion: Mr. Justice Stewart delivered
  the opinion of the Court.
  Once again we are called upon to review a criminal conviction for refusal to answer questions before a subcommittee of the Committee on Un-American Activities of the House of Representatives. See Quinn v. United States, 349 U. S. 155; Emspak v. United States, 349 U. S. 190; Watkins v. United States, 354 U. S. 178; Barenblatt v. United States, 360 U. S. 109; Wilkinson v. United States, 365 U. S. 399; Braden v. United States, 365 U. S. 431. The petitioner was brought to trial in the District Court for the District of Columbia upon an indictment which charged that he had violated 2 U. S. C. § 192 by refusing to answer five questions “which were pertinent to the question then under inquiry” by the subcommittee. He waived a jury and was convicted upon four of the five counts of the indictment. The judgment was affirmed by the Court of Appeals, 108 U. S. App. D. C. 143, 280 F. 2d 691, and we brought the case here because of doubt as to the validity of the conviction in the light of our pre-
  vious decisions. 364 U. S. 812. A careful review of the trial record convinces us that the District Court should have ordered an acquittal.
  At the trial the Government’s case consisted largely of documentary evidence. That evidence showed that a subcommittee of the House Committee on Un-American Activities conducted hearings in Albany, New York, in July of 1953, and again in early April of 1954. The petitioner was not present on either occasion. He was subpoenaed to appear before the subcommittee in Albany on April 9, 1954, but, at the request of his counsel, it was agreed that he should appear instead before the subcommittee three days later in the Old House Office Building in Washington, D. C.
  He appeared there on the appointed day, accompanied by counsel, and without further ado his interrogation began. The petitioner freely answered all preliminary questions, revealing that he was then twenty-four years old and a graduate student at the University of Pennsylvania. He stated that his early education had been in the public schools of Brooklyn, New York, from where he had gone to Cornell University in 1947 for four years as an undergraduate and two additional years as a graduate student.
  The subcommittee’s counsel then ma.de the following statement:
  “Mr. Deutch, during hearings at Albany last week, the committee heard testimony regarding the existence of a Communist Party group or cell operating among undergraduates at Cornell University, among certain graduates at Cornell and in the city of Ithaca.
  “In connection with that testimony, the committee was informed that you were a member of one or more of those groups. If so, I would like to ask you certain matters relating to your activity there.
  “Were you a member of a group of the Communist Party at Cornell ?”
  The petitioner answered, “under protest,” that he had indeed been a member of the Communist Party while at Cornell. He then testified freely and without further objection as to his own activities and associations. He stated that “from the age of 13 or 14 I had read many books on Marxism and at that time was very much impressed with trying to solve certain of the injustices we have nowadays.” He said that when he got to college “I felt if I had ideas I shouldn’t be half pregnant about them, so when I came to college I was approached and joined.” He stated that the approach to join the Party had been made by a student.
  As to the general nature of his Communist Party activities at Cornell, he said “about all that happened were bull sessions on Marxism, and some activities like giving out a leaflet or two. The people I met didn’t advocate the overthrowing of the Government by force and violence, and if they had, I wouldn’t have allowed it.” He testified that he had known one faculty member at Cornell who was a Communist, but that this person had quit the Party. He stated that he had once received from “a personal friend,” who was not connected with the Cornell faculty, a $100 contribution to give to the Party. He stated that he had been the only graduate student at Cornell who was a Communist, and that, as the “head” (and lone member) of the “graduate group,” he had attended meetings in a private house where a “maximum of 4 or 5” people were present. Many of his answers indicated a lack of awareness of the details of Communist activities at Cornell. The petitioner testified that as of the time of the hearings he was no longer a member of the Communist Party, but he volunteered the information that “[t]o a great extent it is only fair to say I am a Marxist today — I don’t want to deny that.”
  While the petitioner’s answers to the many questions put to him about his own activities and conduct were thus fully responsive, he refused to answer five questions he was asked concerning other people. He declined to give the names of the faculty member who had been a Communist, of the friend who had made the $100 contribution, of the student who had originally approached him about joining the Communist Party, and of the owners of the house where the meetings had been held. He also declined to say whether he was acquainted with one Homer Owen. For his refusal to answer these questions he was indicted, tried, and convicted.
  The reason which the petitioner gave the subcommittee for his refusal to answer these questions can best be put in his own words:
  “Sir, I am perfectly willing to tell about my own activities, but do you feel I should trade my moral scruples by informing on someone else? ... I can only say that whereas I do not want to be in contempt of the committee, I do not believe I can answer questions about other people, but only about myself. ... I happen to have been a graduate student — the only one there, and the organization is completely defunct, and the individual you are interested in wasn’t even a professor. The magnitude of this is really beyond reason.”
  The chairman of the subcommittee ruled that it was the petitioner’s duty nevertheless to answer the questions:
  “That decision does not rest with you as to whether or not the scope of this inquiry — as to whether or not certain individuals are important now or not. That is the responsibility of we Representatives to determine. That determination cannot rest with you. It may be very true that the individual to whom you have referred is no longer a member of the Communist Party. However, that is a supposition on your part — and a supposition which the committee cannot accept. ... I think that it is only fair to advise the witness — again advise the witness — that any scruples he may have due to a desire to protect friends and acquaintances, is not a legal reason for declining to answer the questions which are now being put to you, and which will be put to you by counsel.”
  In an effort to prove the pertinence of the questions which the petitioner had refused to answer, the Government offered at the trial the transcripts of the opening statements of Subcommittee Chairman Kearney at the Albany hearings in 1953 and 1954 and of Subcommittee Chairman Velde at a hearing in Chicago in 1954, as well as an additional portion of the transcript of the 1954 Albany hearing. One witness, the counsel for the Committee on Un-American Activities, testified. A review of this evidence convinces us that the Government failed to prove the charge in the indictment that the questions which the petitioner refused to answer were “pertinent to the question then under inquiry” by the subcommittee before which he appeared.
  The Chairman’s opening statement at the Albany hearing in 1953 consisted largely of a paraphrase of the Committee’s authorizing resolution and a general summary of the Committee’s past activities. The only statement of a specific purpose was as follows:
  “The committee, in its course of investigation, came into possession of reliable information indicating Communist Party activities within the Albany area. The committee decided that this information was of such a character as to merit an investigation to determine its nature, extent, character, and objects.”
  At the opening of the Albany hearings in 1954 the Chairman stated that the subcommittee would “resume this morning the investigation of Communist Party activities within the capital area.” He made clear that the hearings were “a continuation of the open hearings which were conducted in Albany” in 1953. He pointed out that testimony at the 1953 hearings had “related to the efforts of the Communist Party to infiltrate industry and other segments of society in the capital area.” “This committee/’ he said, “. . . is investigating communism within the field of labor where it has substantial evidence that it exists.”
  The opening statement of the Chairman of the subcommittee which held hearings in Chicago in 1954 is the same statement that was before this Court in Watkins v. United States, 354 U. S. 178, 210. As was pointed out in the Watkins opinion, Mr. Yelde “did no more than paraphrase the authorizing resolution and give a very general sketch of the past efforts of the Committee.” Moreover, the statement indicated that that subcommittee hearing was directed primarily towards investigation of activities in the Chicago area: “We are here in Chicago, Ill., realizing that this is the center of the great midwestern area of the United States. It cannot be said that subversive infiltration has had a greater, nor a lesser success in infiltrating this important area. The hearings today are the culmination of an investigation that has been conducted by the committee’s competent staff and is a part of the committee’s intention for holding hearings in various parts of the country.”
  The transcripts of part of the testimony of two witnesses at the 1954 Albany hearings, John Marqusee and Emmanuel Richardson, were also introduced at the petitioner’s trial. These transcripts showed that Marqusee’s testimony had related primarily to Communist infiltration of a labor union in Schenectady for which he had worked during a summer vacation in 1948. At that time he had been a student in the New York State School of Industrial and Labor Relations, which, he had testified, was a part of Cornell University. He had told the subcommittee that he had never had any contact with the Communist Party before taking the labor union job. The transcripts showed that he had explained that he had taken the job in accordance with the school’s requirement “that every student should put forth his efforts in securing a job during the summer, during the intervening summers of his 4-year program, 1 summer with a labor union, 1 with a management group, if possible, and 1 summer with a neutral agency, such as a mediation agency or arbitration service.” There was no mention of the Cornell Graduate School, nor of the petitioner, in the transcript of Marqu-see’s testimony.
  The transcript of Richardson’s testimony showed that he had testified that as a student at the Cornell Law School in 1950 he had joined the Communist Party at the request of the Federal Bureau of Investigation. He had named several people he had known as Communists on the Cornell campus, including the petitioner and Homer Owen. He had stated that the petitioner had known a member of the Cornell faculty who was a Communist Party member, and that he had once received through the petitioner a contribution to the Party from someone else of “one hundred and some dollars.” The transcript showed that Richardson had also testified at length concerning Communist infiltration into a labor union in a plant in Syracuse where he had worked during the summers of 1951 and 1952.
  After these transcripts had been introduced at the petitioner’s trial, the Government called its only witness, Frank S. Tavenner, Jr., who had been the “interrogating attorney” at the Albany hearings and at the petitioner’s hearing before the subcommittee in Washington. Mr. Tavenner emphasized that the hearing in Washington was a continuation of the Albany hearings, which he characterized as “a general investigation of Communist Party activities in what was referred to as the 'Capital Area.’ ” Under interrogation of government counsel, the witness expressly disclaimed that the purpose of the Washington hearing had been to investigate Communist activities in educational institutions. He was asked what “connection was there between [the subject of the petitioner’s testimony] and the investigations entitled 'Albany, New York’?” This question was never answered.
  On this record the District Court found the subject under inquiry to be “the infiltration of Communism into educational and labor fields.” .147 F. Supp., at 91. The Court of Appeals never stated what it thought the subject under inquiry by the subcommittee was.
  As our cases make clear, two quite different issues regarding pertinency may be involved in a prosecution under 2 U. S. C. § 192. One issue reflects the requirement of the Due Process Clause of the Fifth Amendment that the pertinency of the interrogation to the topic under the congressional committee’s inquiry must be brought home to the witness at the time the questions are put to him. “Unless the subject matter has been made to appear with undisputable clarity, it is the duty of the investigative body, upon objection of the witness on grounds of perti-nency, to state for the record the subject under inquiry at that time and the manner in which the propounded questions are pertinent thereto.” Watkins v. United States, 354 U. S., at 214-215. See Barenblatt v. United States, 360 U. S., at 123-124. The other and different pertinency issue stems from the prosecution’s duty at the trial to prove that the questions propounded by the congressional committee were in fact “pertinent to the question under inquiry” by the committee. “Undeniably a conviction for contempt under 2 U. S. C. § 192 cannot stand unless the questions asked are pertinent to the subject matter of the investigation.” Barenblatt, supra, at 123. “[T]he statute defines the crime as refusal to answer ‘any question pertinent to the question under inquiry.’ Part of the standard of criminality, therefore, is the pertinency of the questions propounded to the witness.” Watkins, supra, at 208. See Wilkinson v. United States, 365 U. S., at 407-409, 413; Braden v. United States, 365 U. S., at 433, 435-436; Sacher v. United States, 356 U. S. 576, 577; Sinclair v. United States, 279 U. S. 263, 296-297. These two basically different issues must not be blurred by treating them as a single question of “pertinency.”
  With regard to the first issue, it is evident that the petitioner was not made aware at the time he was questioned of the question then under inquiry nor of how the questions which were asked related to such a subject. The chairman made no opening statement, and the petitioner heard no other witnesses testify. The resolution creating the subcommittee revealed nothing. It was merely a general resolution authorizing the creation of a subcommittee to act for the Committee. Committee counsel simply advised the petitioner that the committee had previously heard evidence regarding Communist activity at Cornell, and that he proposed to ask the petitioner “certain matters relating to your activity there.” As to his own activity there the petitioner freely testified. When the petitioner declined to give the names of other people, no clear explanation of the topic under inquiry was forthcoming.
  It is also evident, however, that the thoughts which the petitioner voiced in refusing to answer the questions about other people can hardly be considered as the equivalent of an objection upon the grounds of pertinency. Although he did indicate doubt as to the importance of the questions, the petitioner’s main concern was clearly his own conscientious unwillingness to act as an informer. It can hardly be considered, therefore, that the objections which the petitioner made at the time were “adequate, within the meaning of what was said in Watkins, supra, at 214-215, to trigger what would have been the Subcommittee’s reciprocal obligation had it been faced with a pertinency objection.” Barenblatt, supra, at 124.
  We need not pursue the matter, however, because, in any event, it is clear that the Government at the trial failed to carry its burden of proving the pertinence of the questions. See Bowers v. United States, 92 U. S. App. D. C. 79, 202 F. 2d 447, 452. The first step in proving that component of the offense was to show the subject of the subcommittee’s inquiry. Wilkinson v. United States, 365 U. S., at 407. As related above, the Government offered documentary evidence of statements made by the chairman of the subcommittees at two hearings in Albany which tended to show that those subcommittees were investigating Communist infiltration in the Albany or “capital” area, particularly in the field of labor. The Government presented one witness who testified that the petitioner’s hearing was a continuation of the Albany hearings, and that the subject of those hearings was Communist infiltration in the Albany area. He disavowed any implication that the topic under inquiry was Communism either at Cornell or in educational institutions generally.
  Yet the questions which the petitioner was convicted of refusing to answer obviously had nothing to do with the Albany area or with Communist infiltration into labor unions. It can hardly be seriously contended that Cornell University is in the Albany area. Indeed, we may take judicial notice of the fact that Ithaca is more than one hundred and sixty-five miles from Albany, and in an entirely different economic and geographic area of New York. The petitioner was asked nothing about Albany or the Albany area. So far as the record shows, he knew nothing about that subject. He was asked nothing about labor or labor unions. So far as the record shows, he knew nothing about them. He was asked nothing about any possible connection between Cornell or its graduate school and Communist infiltration in Albany. Yet the petitioner was basically a cooperative witness, and there is nothing in the record to indicate that, except for giving the names of others, he would not have freely answered any inquiry the subcommittee wished to pursue with respect to these subjects. It is true that the transcript of the testimony of two witnesses at the Albany hearings established that, in addition to testifying about Communist infiltration into labor unions in the Albany area, they had been willingly led into some testimony about Communist activities by the petitioner and others at Cornell. But that excursion can hardly justify a disregard of the Government’s careful proof at the petitioner’s trial of what the subject under inquiry actually was. The pertinence of the interrogation of those two witnesses is not before us. The pertinence of the petitioner’s interrogation is.
  In enacting 2 U. S. C. § 192, the Congress invoked the aid of the federal judicial system to protect itself from contumacious conduct. Watkins, supra, at 207. “In fulfillment of their obligation under this statute, the courts must accord to the defendants every right which is guaranteed to defendants in all other criminal cases.” Id., at 208. “One of the rightful boasts of Western civilization is that the [prosecution] has the burden of establishing guilt solely on the basis of evidence produced in court and under circumstances assuring an accused all the safeguards of a fair procedure.” Irvin v. Dowd, 366 U. S. 717, 729 (concurring opinion). Among these is the presumption of the defendant’s innocence. Sinclair v. United States, 279 U. S., at 296-297; Flaxer v. United States, 358 U. S., at 151. It was incumbent upon the prosecution in this case to prove that the petitioner had committed the offense for which he was indicted. One element of that offense was the pertinence to the subject matter under inquiry of the questions the petitioner refused to answer. We hold, as a matter of law, that there was a failure of such proof in this case. Sacher v. United States, 356 U. S. 576; see Sinclair v. United States, 279 U. S., at 298-299; Braden v. United States, 365 U. S., at 436-437.
  We do not decide today any question respecting the power or legislative purpose of this subcommittee of the House Un-American Activities Committee. Nor do we reach the large issues stirred by the petitioner’s First Amendment claims. Our decision is made within the conventional framework of the federal criminal law, and in accord with its traditional concepts. In a word, we hold only that the Government failed to prove its case.
  Reversed.
  “Every person who having been summoned as a witness by the authority of either House of Congress to give testimony or to produce papers upon any matter under inquiry before either House, or any joint committee established by a joint or concurrent resolution of the two Houses of Congress, or any committee of either House of Congress, willfully makes default, or who, having appeared, refuses to answer any question pertinent to the question under inquiry, shall be deemed guilty of a misdemeanor, punishable by a fine of not more than $1,000 nor less than $100 and imprisonment in a common jail for not less than one month nor more than twelve months.” 2 U. S. C. § 192.
  See, in addition to the cases cited in the text, supra: Sinclair v. United States, 279 U. S. 263; United States v. Bryan, 339 U. S. 323; United States v. Fleischman, 339 U. S. 349; United States v. Rumely, 345 U. S. 41; Sacher v. United States, 356 U. S. 576; Flaxer v. United States, 358 U. S. 147. See also McPhaul v. United States, 364 U. S. 372.
  “I will answer that question, but only under protest.
  “I wish to register a challenge as to the jurisdiction of this committee under Public Law 601, which is the committee’s enabling legislation. This question, or any similar questions involving my associations, past or future, I am answering, but only under protest as to its constitutionality. But, under your jurisdiction as stated, I answer yes, I was a member of the Communist Party.”
  The following colloquies are typical:
  “Mr. Doyle: Who published the leaflets?
  “Mr. Deutch: I believe the Communist Party published them.
  “Mr. Doyle: What Communist Party? Where did you get the leaflets? From the national headquarters?
  “Mr. Deutch: I don’t believe so. It was a local branch.
  “Mr. Doyle: Where was the office of the local branch from which you got these leaflets?
  “Mr. Deutch: I didn’t know where it was. I was just asked to distribute them.”
  “Mr. Tavenner: Were you ever a member of the Downtown Club of the Communist Party in Ithaca?
  “Mr. Deutch: I don’t believe so.
  “Mr. Tavenner: Did you attend meetings of that group?
  “Mr. Deutch: No. That is, I don’t believe so. The reason I wonder is because that organization became defunct so that there was really no organization. Downtown was Uptown, and there were so few people that I just want to qualify that statement.”
  “Mr. Scherer: Let me ask you this question. You knew where the meetings were held?
  “Mr. Deutch: I don’t believe I know exactly where they were. This is because — since Mr. Richardson drove me there.” [Mr. Richardson was a law student at Cornell who had joined the Communist Party at the behest of the Federal Bureau of Investigation. See p. 466, infra.']
  The questions, as set out in the five counts of the indictment, were as follows:
  “Count One
  “The committee was advised that a witness by the name of Ross Richardson has stated that you acted as liaison between a Communist Party group on the campus and a member of the faculty at Cornell, and that you knew the name of the member of that faculty, who was a member of the Communist Party. Will you tell us who that member of the faculty was?
  “Count Two
  “Will you tell the committee, please, the source of that $100 contribution, if it was made?
  “Count Three
  “Where were these meetings held?
  “Count Four
  “Were you acquainted with Homer Owen?
  “Count Five
  “The witness is directed to give the name of the person by whom he was approached.”
  The petitioner was convicted on all but Count Three.
  “The committee is charged by the Congress of the United States with the responsibility of investigating the extent, character and objects of un-American propaganda activities in the United States, the diffusion within the United States of subversive and un-American propaganda that is instigated from foreign countries, or of a domestic origin, and attacks the principles of the form of government as guaranteed by our Constitution and all other questions in relation thereto that will aid Congress in any necessary remedial legislation.
  “It has been fully established by testimony before this and other congressional committees and before the courts of our land that the Communist Party of the United States is part of an international conspiracy, which is being used as a tool or a weapon by a foreign power to promote its own foreign policy and which has for its objective the overthrow of the governments of all non-Communist countries, resorting to the use of force and violence if necessary. This organization cannot live and expand within the United States except by the promulgation and diffusion of subversive and un-American propaganda designed to win adherence to its cause. .
  “The first witness in this hearing will testify regarding certain aspects of the worldwide Communist conspiracy, which should demonstrate what a serious matter it is to permit individuals who are subject to the directives and discipline of the Communist Party to be placed in positions of leadership in any functional organization.
  “The committee, in its course of investigation, came into possession of reliable information indicating Communist Party activities within the Albany area. The committee decided that this information was of such a character as to merit an investigation to determine its nature, extent, character, and objects.
  “Many witnesses have appeared before this committee, sitting in various places throughout the United States, and have revealed their experiences as former Communist Party members. Such testimony has added immeasurably to the sum total of the knowledge, character, extent, and objects of Communist activities in this country.
  “Witnesses from Hollywood, labor unions, the legal profession, medical profession, and other groups have made a great contribution to the defense of our country by disclosing to this committee facts within their knowledge.
  “In the view of this committee, such testimony should not be held against an individual where it has that character of trustworthiness which convinces one that the witness has completely and finally terminated Communist Party membership and that such testimony has been given in all good faith.
  “The committee is not concerned with the political beliefs or opinions of any witness who has been called before it. It is concerned only with the facts showing the extent, character, and objects of the Communist Party activities.
  “In keeping with the long-standing policy of this committee, any individual or organization whose name is mentioned during the course of the hearings in such a manner as to adversely affect them shall have an opportunity to appear before the committee for the purpose of making a denial or explanation of any adverse references.
  “I would also like at this time, before the beginning of these hearings, to make this announcement to the public: We are here at the discretion of the Congress of the United States, trying to discharge a duty and obligation that has been placed upon us. The public is here by permission of the committee and not by any compulsion. Any attempt or effort on the part of anyone to make a demonstration or audible comment in this hearing room, either favorably or unfavorably, toward the committee’s undertaking, or to what any witness may have to say, will not be countenanced by the committee. If such conduct should occur, the officers on duty will be requested to eject the offenders from the hearing room.”
  The entire statement of Mr. Velde is set out at 354 U. S, 210-211, n. 49.
  Schenectady is sixteen miles from Albany.
  The subcommittee before which the petitioner appeared, “for the purpose of taking this testimony this morning,” consisted of Representative Jackson, Acting Chairman, and Representatives Scherer and Doyle. The subcommittee which had conducted the hearings at Albany a few days earlier was composed of Representative Kearney, Chairman, and Representatives Scherer and Walter.
  “Q. How does it happen that Mr. Deutch’s testimony appears in ‘Education — 8’ if it was a part actually of ‘Albany’ ?
  “A. Well, the staff in the releasing of this testimony at a later date placed it for convenience under the heading of Education.”
  We disregard the evidence indicating that the subject under inquiry was Communist activities in the Chicago area.
  This was hardly a matter within the peculiar knowledge of the petitioner. Cf. McPhaul v. United States, 364 U. S. 372, 379.
  For a Court opinion specifically to join issue with what is written in dissent is a practice ordinarily to be avoided. One of the dissenting opinions in this case, however, is largely based upon what are asserted to be “the undisputed relevant facts in the record.” Since every litigant is entitled to have his case reviewed on the facts in the record, it is appropriate to state explicitly that:
  (1) The record affirmatively shows that neither Marqusee nor Richardson testified, directly or indirectly, to “passing out handbills at strike scenes” or to any “plan of using the prestige and innocent aid of the university’s placement service in getting summer jobs with labor unions in upper New York,” or anywhere else.
  (2) The record affirmatively shows that at no time did the subcommittee, or anyone on its behalf, “advise” the petitioner, or anyone else, that the subcommittee was investigating the infiltration of communism into the “educational and labor fields.”
choices: First Amendment, miscellaneous (cf. comity: First Amendment) commercial speech, excluding attorneys libel, defamation: defamation of public officials and public and private persons libel, privacy: true and false light invasions of privacy legislative investigations: concerning internal security only federal or state internal security legislation: Smith, Internal Security, and related federal statutes loyalty oath or non-Communist affidavit (other than bar applicants, government employees, political party, or teacher) loyalty oath: bar applicants (cf. admission to bar, state or federal or U.S. Supreme Court) loyalty oath: government employees loyalty oath: political party loyalty oath: teachers security risks: denial of benefits or dismissal of employees for reasons other than failure to meet loyalty oath requirements conscientious objectors (cf. military draftee or military active duty) to military service campaign spending (cf. governmental corruption): protest demonstrations (other than as pertains to sit-in demonstrations): demonstrations and other forms of protest based on First Amendment guarantees free exercise of religion establishment of religion (other than as pertains to parochiaid:) parochiaid: government aid to religious schools, or religious requirements in public schools obscenity, state (cf. comity: privacy): including the regulation of sexually explicit material under the 21st Amendment obscenity, federal