opinion: Mr. Justice Minton
  delivered the opinion of the Court.
  The question we have for determination here is whether a challenge for cause to jurors on voir dire because of employment by the Federal Government should have been sustained under the circumstances of this case.
  Petitioner was convicted of violating R. S. § 102, 2 U. S. C. § 192, for willfully failing to appear before the Committee on Un-American Activities of the House of Representatives in compliance with a subpoena duly served upon him. The Court of Appeals affirmed, 84 U. S. App. D. C. 31, 171 F. 2d 986. We granted certiorari limited to the question whether Government employees could properly serve on the jury which tried petitioner. 337 U. S. 954.
  Petitioner voluntarily appeared before the House Committee on Un-American Activities which had under consideration two bills to outlaw the Communist Party. Petitioner was and is General Secretary of the Communist Party of the United States. On his voluntary appearance before the Committee, petitioner refused to answer questions as to his name and the date and place of his birth. The Chairman of the Committee directed that a subpoena be served forthwith upon petitioner, requiring him to appear before the Committee on April 9, 1947. On the appointed date petitioner sent a representative but did not appear in accordance with the subpoena. The Committee reported his refusal to appear to the House of Representatives, and the House adopted a resolution certifying the report of the Committee to the United States Attorney for the District of Columbia. Petitioner was subsequently indicted.
  When the case was called for trial, petitioner made a motion for transfer upon the ground that he could not obtain a fair and impartial trial in the District of Columbia. In his affidavit supporting the motion, he posited this contention mainly on the ground that Government employees, who comprise a large part of the District’s population, are subject to Executive Order 9835, 12 Fed. Reg. 1935, providing standards for their discharge upon reasonable grounds for belief that they are disloyal to the Government of the United States. He argued that Government employees would be afraid to risk the charge of disloyalty or possible termination of employment which would allegedly flow from a vote for acquittal. The motion for a transfer was denied.
  Both sides conducted further voir dire examination at the conclusion of the court’s questioning of the panel. Attorney for petitioner questioned individually each member of the panel who indicated that he was employed by the Government. He then challenged for cause all Government employees. The court denied the challenge. Petitioner exercised two of his three peremptory challenges against Government employees. He exhausted all his peremptory challenges. Seven of the twelve finally selected were Government employees. Each of the seven expressed the belief that he could render a fair and impartial verdict.
  Is petitioner entitled to a new trial because his challenge to the Government employees for cause was not sustained? The question of the presence of Government employees on District of Columbia juries is not a new controversy. It has been before this Court on three previous occasions. Crawford v. United States, 212 U. S. 183; United States v. Wood, 299 U. S. 123; Frazier v. United States, 335 U. S. 497. In the Crawford case the defendants were charged with a conspiracy to defraud the United States. The Court held that the statute prescribing the eligibility of jurors in the District of Columbia did not control the subject. The Court turned to the common law in force in Maryland when the District was formed, and found that a servant was subject to challenge for cause at common law where the master was party to the case on trial. In such a case, bias would be implied as a matter of law. The Court concluded that it was error to deny a challenge for cause to a Government employee in a case to which the Government was a party.
  In 1935 Congress, prompted by the paucity of qualified jurors which resulted from the Crawford decision, passed an Act redefining eligibility for jury service in the District of Columbia. After exempting certain classes, the Act provided: “All other persons, otherwise qualified according to law whether employed in the service of the Government of the United States or of the District of Columbia . . . shall be qualified to serve as jurors in the District of Columbia and shall not be exempt from such service . . . 49 Stat. 682, D. C. Code, § 11-1420 (1940).
  The constitutionality of this Act was sustained in United States v. Wood, 299 U. S. 123, where the defendant was charged with petty larceny from a private corporation. The defendant contended that the presence of Government employees on the jury denied the right of trial by an impartial jury within the meaning of the Sixth Amendment to the Constitution of the United States. He pointed out that under the common law as expounded by Blackstone, a King’s servant and therefore a Government employee could not serve on a jury, and he argued that this view was carried into the Sixth Amendment.
  Chief Justice Hughes, speaking for the Court, meticulously examined the problem. He found that Blackstone’s statement of disqualification had reference only to servants of private parties, and that there was no established practice with respect to the King’s servants at common law. The Court was of the view that even if such a common law disqualification existed, Congress had power to remove it. Unlike the statute in the Crawford case, the 1935 Act left no doubt that Congress intended to qualify Government employees as jurors. The constitutionality of such a declaration was presented for the first time. The opinion carefully emphasized that the Act left accused persons free to show the existence of actual bias. Only the question of implied bias was presented. The Court concluded that the guarantee of an impartial jury was not impaired, stating:
  “It is manifest that the Act was passed to meet a public need and that no interference with the actual impartiality of the jury was contemplated. The enactment itself is tantamount to a legislative declaration that the prior disqualification was artificial and not necessary to secure impartiality. ... To impute bias as matter of law to the jurors in question here would be no more sensible than to impute bias to all storeowners and householders in cases of larceny or burglary.” United States v. Wood, supra, 148-149, 150.
  Only last term in Frazier v. United States, 335 U. S. 497, the problem of jury service by Government employees was reexamined. There the defendant was tried and convicted of violating the Narcotics Act by a jury of the District of Columbia composed entirely, due to circumstances fortuitous or otherwise, of Federal Government employees. Mr. Justice Rutledge, speaking for the Court, reexamined the rule of the Wood case that Government employees are not disqualified as a matter of law from serving on a jury in a case to which the Government is a party. Government employees were again held to be subject to challenge only for “actual bias.”
  It would be a work of supererogation to attempt to clarify the statement of the law after the Wood and Frazier cases. Some may doubt the wisdom of the Court’s decision in laying down the rule, but there can be no doubt that this Court has spoken very clearly, not only once, but twice.
  No question of actual bias is before us. The way is open in every case to raise a contention of bias from the realm of speculation to the realm of fact. In both the Wood and Frazier cases this Court stressed that while impaneling a jury the trial court has a serious duty to determine the question of actual bias, and a broad discretion in its rulings on challenges therefor. United States v. Wood, supra, 133-134, 150; Frazier v. United States, supra, 511-512. We reaffirm those principles. In exercising its discretion, the trial court must be zealous to protect the rights of an accused. And we agree that this the court must do without reference to an accused’s political or religious beliefs, however such beliefs may be received by a predominant segment of our population. Ideological status is not an appropriate gauge of the high standard of justice toward which our courts may not be content only to strive. But while one of an unpopular minority group must be accorded that solicitude which properly accompanies an accused person, he is not entitled to unusual protection or exception.
  Petitioner asserts that in order to secure the constitutional guarantee of trial by an impartial jury all Government employees must be held, in the special circumstances of this case, to be biased as a matter of law. It is not contended that bias appears as a fact from the record. As far as it appears, the court was willing to consider any evidence which would indicate that investigatory agencies of the Government had recognized in the past or would take cognizance in the future of a vote of acquittal, but no such proof was made. Nor was there evidence with respect to the existence of a climate of opinion among Government employees that they would jeopardize their tenure or provoke investigation by such a verdict. Rather petitioner asks that bias be implied from the recitation of the following circumstances: He is a Communist; the instigator of the charges is the Un-American Activities Committee which allegedly would take notice of a vote for acquittal; the issue in the case- is contempt of Congress; in contempt cases the Government’s interest is the vindication of a direct affront, as distinguished from its role in an ordinary prosecution. But petitioner primarily bases his case on a request, in effect, that judicial notice be taken of an aura of surveillance and intimidation which is said to exist in the District because of Executive Order 9835, outstanding at the time of the trial.
  The "Loyalty Order,” as it is popularly known, requires the investigation of all persons entering civilian employment with the United States; as to those already in service, heads of departments and agencies are charged with the duty of making certain that disloyal persons are not retained. Petitioner maintains that because of this Order, Government employees would be hesitant to vote for acquittal because such action might be interpreted as “sympathetic association” with Communism.
  Of course, the Loyalty Order could be the subject of judicial notice. Such notice, however, would give only limited illumination. It is proper to observe that the Loyalty Order is not directed solely against Communists, and that the crime of which petitioner was convicted is not a crime peculiar to Communists. Further, the Loyalty Order preceded the instant trial only by about three months. It was promulgated by the President on March 21, 1947. This trial began on June 23, 1947, and was concluded on June 26, 1947. On May 9, 1947, the President submitted to Congress a request for an appropriation to carry out the Loyalty Order, which was not enacted into law until July 31, 1947. It was not until August 18, 1947, that Standard Form 84, requesting certain pertinent information from each federal employee, was made available.
  The administrative implementation of Executive Order 9835, which was yet to come, was apparently not the subject of anticipatory fear by these jurors. Their answers to interrogatories on the influence of the Loyalty Order were categorically to the contrary. We must credit these representations, and this is particularly so in the absence of any evidence which would indicate an opposite opinion among Government employees. One may not know or altogether understand the imponderables which cause one to think what he thinks, but surely one who is trying as an honest man to live up to the sanctity of his oath is well qualified to say whether he has an unbiased mind in a certain matter.
  Ultimately, petitioner’s contentions amount to this: Since he is a Communist, in view of all the surrounding circumstances an exception must be carved out of the rule laid down in the statute, and construed in Wood and Frazier, that there is no implied bias by reason of Government employment. Thus the rule would apply to anyone but a Communist tried for contempt of a congressional committee, but not to a Communist. We think the rule in Wood and Frazier should be uniformly applied. A holding of implied bias to disqualify jurors because of their relationship with the Government is no longer permissible. The Act makes no exception for distinctive circumstances. It states that: “All . . . persons . . . whether employed in the service of the Government of the United States or of the District of Columbia . . . shall be qualified to serve as jurors in the District of Columbia and shall not be exempt from such service . . . .” Preservation of the opportunity to prove actual bias is a guarantee of a defendant’s right to an impartial jury. We adhere to our holding that the enactment of the statute is within the power of Congress, and that therefore employees of the Federal Government are not challengeable solely by reason of their employment.
  It follows that we are unable to conclude that the failure to sustain the challenge for cause denied petitioner an “impartial jury.” “Impartiality is not a technical conception. It is a state of mind. For the ascertainment of this mental attitude of appropriate indifference, the Constitution lays down no particular tests and procedure is not chained to any ancient and artificial formula.” United States v. Wood, supra, 145-146. In this case, no more than the trial court can we without injustice take judicial notice of a miasma of fear to which Government employees are claimed to be peculiarly vulnerable— and from which other citizens are by implication immune. Vague conjecture does not convince that Government employees are so intimidated that they cringe before their Government in fear of investigation and loss of employment if they do their duty as jurors, which duty this same Government has imposed upon them. There is no disclosure in this record that these jurors did not bring to bear, as is particularly the custom when personal liberty hinges on the determination, the sense of responsibility and the individual integrity by which men judge men.
  The judgment is
  Affirmed.
  Mr. .Justice Douglas and Mr. Justice Clark took no part in the consideration or decision of this case.
  H. R. Doc. No. 242, 80th Cong., 1st Sess. (1947); 93 Cong. Rec. 4977 (1947).
  61 Stat. 696, 700. See Investigations Subcommittee on Expenditures, Investigation of Federal Employees Loyalty Program, S. Rep. No. 1775, 80th Cong., 2d Sess. (1948).
  Federal Personnel Manual 12-4. In a press release dated November 7, 1947, the Civil Service Commission announced the appointment of the Loyalty Review Board. A statement of the Board with respect to its regulations was published on January 20, 1948. 13 Fed. Reg. 253.
  “Mr. McCabe: You are familiar with the Government loyalty oath investigation?
  “Juror Holford: I believe I am. I have heard something of it.
  “Mr. McCabe: Do you feel that rendering a verdict of not guilty in this case, if you come to that conclusion, it would stop you, any criticism or embarrassment among your fellow employees?
  “Juror Holford: None whatsoever.
  “Mr. McCabe: Or by your superiors?
  “Juror Holford: No.
  * “Mr. McCabe: You would not have any thought that would be taken as evidence of friendliness to communism?
  “Juror Holford: No; I am not worried about my job that way.”
  “Mr. McCabe: Now, Mr. Jones, you have heard, have you, of the loyalty test or loyalty investigation which is going on to test the loyalty of Government employees? Have you heard of that?
  “Mr. Jones: Yes, I have.
  “Mr. McCabe: Are you aware of the fact that one of the tests that might disqualify or prevent you from Government employment is friendly association with any Communist person or any Communist organizations?
  “Mr. Jones: That would not. I am a Civil Service employee. I have taken an examination for my job.
  “Mr. McCabe: Yes. Are you aware of the fact that, despite any Civil Service protection, still a finding that you were in friendly association with any Communist or Communist organization would render you ineligible to continue in your Government position?
  “Mr. Jones: It would not.
  “Mr. McCabe: What?
  “Mr. Jones: It would not.”
  The replies of the other jurors were in a similar vein.
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