opinion: Mr. Chief Justice Warren
  delivered the opinion of the Court.
  This is a companion case to Quinn v. United States, ante, p. 155. Challenged in each proceeding is a conviction under 2 U. S. C. § 192 in the District Court for the District of Columbia. The two cases arose out of the same investigation by the Committee on Un-American Activities of the House of Representatives. Because of the similarity of the legal issues presented, the cases were consolidated for argument in this Court.
  Pursuant to subpoena, petitioner appeared on December 5, 1949, before a subcommittee of the Committee on Un-American Activities. The subcommittee consisted of a single member, Rep. Morgan M. Moulder. Petitioner was then the General Secretary-Treasurer of the United Electrical, Radio & Machine Workers of America as well as Editor of the UE News, the union’s official publication. The subcommittee’s hearings had previously been announced as concerning “the question of Communist affiliation or association of certain members” of the union and “the advisability of tightening present security requirements in industrial plants working on certain Government contracts.”
  Petitioner was asked a total of 239 questions. Most dealt with the structure of the union, the duties of its officers, the scope of its membership and bargaining commitments, the alleged similarity in policies of the UE News and the Communist Party, the non-Communist affidavit that petitioner had filed with the National Labor Relations Board, and related matters. Petitioner answered all of these questions. He declined, however, to answer 68 of the 239 questions. These 68 questions dealt exclusively with petitioner’s associations and affiliations. He based his refusal on “primarily the first amendment, supplemented by the fifth.” Of the 68 questions, 58 asked in substance that he state whether or not he was acquainted with certain named individuals and whether or not those individuals had ever held official positions in the union. Two of the questions concerned petitioner’s alleged membership in the National Federation for Constitutional Liberties and the Civil Rights Congress. Eight questions concerned petitioner’s alleged membership and activity in the Communist Party.
  On November 20, 1950, petitioner was indicted under § 192 for his refusal to answer the 68 questions. Sitting without a jury, the District Court held that petitioner’s references to “primarily the first amendment, supplemented by the fifth” were insufficient to invoke the Fifth Amendment’s privilege against self-incrimination. The District Court accordingly found petitioner guilty on all 68 counts and sentenced him to a term of six months and a fine of $500. The Court of Appeals for the District of Columbia Circuit, three judges dissenting, affirmed en banc. From that decision this Court granted certiorari.
  I.
  As pointed out in Quinn v. United States, supra, no ritualistic formula or talismanic phrase is essential in order to invoke the privilege against self-incrimination. All that is necessary is an objection stated in language that a committee may reasonably be expected to understand as an attempt to invoke the privilege. In the Quinn case we hold that Quinn’s references to “the First and Fifth Amendments” and “the First Amendment to the Constitution, supplemented by the Fifth Amendment” were sufficient to meet this standard. It would be unwarranted, we think, to reach a different conclusion here as to petitioner’s plea based on “primarily the first amendment, supplemented by the fifth.”
  The Government does not even attempt to distinguish between the two cases in this respect. Apparently conceding that petitioner as well as Quinn intended to invoke the privilege, the Government points out “the probability” that his references to the Fifth Amendment were likewise deliberately phrased in muffled terms “to obtain the benefit of the privilege without incurring the popular opprobrium which often attaches to its exercise.” On this basis the Government contends that petitioner’s plea was not adequate. The answer to this contention is threefold. First, an objection that is sufficiently clear to reveal a probable intention to invoke the privilege cannot be ignored merely because it is not phrased in an orthodox manner. Second, if it is true that in these times a stigma may somehow result from a witness’ reliance on the Self-Incrimination Clause, a committee should be all the more ready to recognize a veiled claim of the privilege. Otherwise, the great right which the Clause was intended to secure might be effectively frustrated by private pressures. Third, it should be noted that a committee is not obliged to either accept or reject an ambiguous constitutional claim the very moment it is first presented. The way is always open for the committee to inquire into the nature of the claim before making a ruling. If the witness intelligently and unequivocally waives any objection based on the Self-Incrimination Clause, or if the witness refuses a committee request to state whether he relies on the Self-Incrimination Clause, he cannot later invoke its protection in a prosecution for contempt for refusing to answer that question.
  The Government argues that petitioner did in fact waive the privilege, at least as to one count of the indictment, and that the conviction can be sustained on that count alone. In response to a question concerning his associations, petitioner expressed apprehension that the committee was “trying to perhaps frame people for possible criminal prosecution” and added that “I think I have the right to reserve whatever rights I have . . . .” The following colloquy then took place:
  “Mr. Moulder. Is it your feeling that to reveal your knowledge of them would subject you to criminal prosecution?
  “Mr. Emspak. No. I don’t think this committee has a right to pry into my associations. That is my own position.”
  Petitioner’s reply, it is contended, constituted an effective disclaimer of the privilege. We find this contention without merit. As this Court declared in Smith v. United States, 337 U. S. 137, 150: “Although the privilege against self-incrimination must be claimed, when claimed it is guaranteed by the Constitution. . . . Waiver of constitutional rights ... is not lightly to be inferred. A witness cannot properly be held after claim to have waived his privilege . . . upon vague and uncertain evidence.”
  The Smith case, we believe, is controlling here. The witness in that case, at the outset of questioning by an OPA examiner, stated “I want to claim privilege as to anything I say.” The examiner accepted this statement as a plea of possible self-incrimination and a request for the immunity afforded to involuntary witnesses by the Price Control Act of 1942.. The questioning proceeded on that basis. In response to one question, however, the witness made a statement that appeared to the examiner to be voluntary. This colloquy then ensued:
  “Question: This is a voluntary statement. You do not claim immunity with respect to that statement?
  “Answer: No.”
  In a subsequent prosecution of the witness for violation of the Price Control Act, it was held that his “No” answer waived his immunity at least as to the one statement. This Court unanimously reversed, stating (337 U. S., at 151): “Without any effort to clarify the 'No,’ the examiner went ahead and had the witness restate the substance of the long answer . . . without any further intimation that the subsequent answers were considered by the examiner to be voluntary. We do not think under these circumstances this equivocal ‘No’ is a waiver of the previous definite claim of general privilege against self-incrimination.” Similarly, in the instant case, we do not think that petitioner’s “No” answer can be treated as a waiver of his previous express claim under the Fifth Amendment. At most, as in the Smith case, petitioner’s “No” is equivocal. It may have merely represented a justifiable refusal to discuss the reasons underlying petitioner’s assertion of the privilege; the privilege would be of little avail if a witness invoking it were required to disclose the precise hazard which he fears. And even if petitioner’s “No” answer were taken as responsive to the question, the answer would still be consistent with a claim of the privilege. The protection of the Self-Incrimination Clause is not limited to admissions that “would subject [a witness] to criminal prosecution”; for this Court has repeatedly held that “Whether such admissions by themselves would support a conviction under a criminal statute is immaterial” and that the privilege also extends to admissions that may only tend to incriminate. In any event, we cannot say that the colloquy between the committee and petitioner was sufficiently unambiguous to warrant finding a waiver here. To conclude otherwise would be to violate this Court’s own oft-repeated admonition that the courts must “indulge every reasonable presumption against waiver of fundamental constitutional rights.”
  Throughout this entire proceeding — in the trial in the District Court, on appeal in the Court of Appeals, and here on certiorari — the Government has never denied that petitioner would be entitled to the protection of the privilege if he did in fact invoke it. And during argument in this Court the Government expressly conceded that all 68 questions were of an incriminatory character. In addition, neither the District Court nor the Court of Appeals saw fit to introduce the issue into the case. We are therefore reluctant to do so now. But doubts on the issue by some members of the Court make its consideration necessary.
  “To sustain the privilege,” this Court has recently held, “it need only be evident from the implications of the question, in the setting in which it is asked, that a responsive answer to the question or an explanation of why it cannot be answered might be dangerous because injurious disclosure could result.” And nearly 150 years ago Chief Justice Marshall enunciated a similar test: “Many links frequently compose that chain of testimony which is necessary to convict any individual of a crime. It appears to the court to be the true sense of the rule that no witness is compellable to furnish any one of them against himself.” Applying this test to the instant case, we have no doubt that the eight questions concerning petitioner’s alleged membership in the Communist Party fell within the scope of the privilege. The same is true of the two questions concerning petitioner’s alleged membership in the National Federation for Constitutional Liberties and the Civil Rights Congress; both organizations had previously been cited by the committee as Communist-front organizations. There remains for consideration the 58 questions concerning petitioner’s associations. This Court has already made abundantly clear that such questions, when asked in a setting of possible incrimination, may fall within the scope of the privilege.
  What was the setting — as revealed by the record — in which these questions were asked? Each of the named individuals had previously been charged with having Communist affiliations. On October 14, 1949, less than two months prior to petitioner’s appearance before the committee, eleven principal leaders of the Communist Party in this country had been convicted under the Smith Act for conspiring to teach and advocate the violent overthrow of the United States. Petitioner was identified at their trial as a Communist and an associate of the defendants. It was reported that Smith Act indictments against other Communist leaders were being prepared. On November 23, 1949, two weeks prior to petitioner’s appearance, newspapers carried the story that the Department of Justice “within thirty days” would take “an important step” toward the criminal prosecution of petitioner in connection with his non-Communist affidavit filed with the National Labor Relations Board.
  Under these circumstances, it seems clear that answers to the 58 questions concerning petitioner’s associations “might be dangerous because injurious disclosure could result.” To reveal knowledge about the named individuals — all of them having been previously charged with Communist affiliations — could well have furnished “a link in the chain” of evidence needed to prosecute petitioner for a federal crime, ranging from conspiracy to violate the Smith Act to the filing of a false non-Coxnmunist affidavit under the Taft-Hartley Act. That being so, it is immaterial that some of the questions sought information about associations that petitioner might have been able to explain away on some innocent basis unrelated to Communism. If an answer to a question may tend to be incriminatory, a witness is not deprived of the protection of the privilege merely because the witness if subsequently prosecuted could perhaps refute any inference of guilt arising from the answer.
  II.
  There is here, as in the Quinn case, a second ground for our decision. At no time did the committee specifically overrule petitioner’s objection based on the Fifth Amendment, nor did the committee indicate its overruling of the objection by specifically directing petitioner to answer. In the absence of such committee action, petitioner was never confronted with a clear-cut choice between compliance and noncompliance, between answering the question and risking prosecution for contempt. For the reasons set out in the Quinn opinion, we believe the committee — by failing to meet these minimal procedural standards, originally recognized by the committee and recently re-adopted — did not adequately apprise petitioner that an answer was required notwithstanding his objections. And without such apprisal, there is lacking the element of deliberateness necessary for a conviction under § 192 for a refusal to answer.
  III.
  Our disposition of the case makes it unnecessary to pass on petitioner’s other contentions as to the First Amendment and the grand jury. The judgment below is reversed and the case remanded to the District Court with directions to enter a judgment of acquittal.
  Reversed.
  [For dissenting opinion of Mb. Justice Reed, joined by Mr. Justice Minton, insofar as it applies to this case, see ante, p. 171.]
  Section 192 provides:
  “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.”
  Hearings before House Committee on Un-American Activities Regarding Communist Infiltration of Labor Unions, 81st Cong., 1st Sess., Part I, 541-542.
  At the very outset of this line of questioning, the following colloquy took place:
  “Mr. Moulder. Are you going to answer the question?
  “Mr. Emspak. Because of the hysteria, I think it is my duty to endeavor to protect the rights guaranteed under the Constitution, primarily the first amendment, supplemented by the fifth. This committee will corrupt those rights.” (Italics added.)
  Hearings, supra, note 2, Part II, at 839.
  Petitioner’s motions to dismiss the indictment were denied. United States v. Emspak, 95 F. Supp. 1010, 1012.
  United States v. Emspak, unreported, Criminal No. 1742-50 (D. D. C.). In a companion case under § 192, United States v. Matles, unreported, Criminal No. 1745-50 (D. D. C.), the same district judge directed an acquittal of James J. Matles, a UE official who testified before the committee on the same day as Emspak and who similarly relied on “the First and Fifth Amendments.” Hearings, supra, note 2, Part II, at 856. The court held that Matles’ plea was sufficient to invoke the Self-Incrimination Clause because it appeared that Rep. Moulder so understood it.
  91 U. S. App. D. C. 378, 203 F. 2d 54.
  346 U. S. 809. After argument, the case was restored to the docket for reargument. 347 U. S. 1006.
  Brief for United States, p. 33, in Quinn v. United States, ante, p. 155.
  Petitioner’s general sentence on all 68 counts was less than the maximum permissible on any count. See Sinclair v. United States, 279 U. S. 263, 299.
  Hearings, supra, note 2, Part II, at 840.
  Id., at 841.
  United States v. Daisart Sportswear, Inc., 169 F. 2d 856, 862-863 (C. A. 2d Cir.).
  See also United States v. St. Pierre, 128 F. 2d 979, 980 (C. A. 2d Cir.), from which this Court’s Smith opinion approvingly quotes the following: “Nor is it material that appellant stated at several points that he had committed no federal crime; such a contradiction, especially by a nervous or excitable witness would not overcome a clear claim of privilege if he was otherwise entitled to the privilege.”
  Cf. United States v. Weisman, 111 F. 2d 260, 261 (C. A. 2d Cir.).
  See Hoffman v. United States, 341 U. S. 479, 486; United States v. Burr, 25 Fed. Cas. 38, at 40, No. 14,692e.
  Blau v. United States, 340 U. S. 159, 161.
  See Hoffman v. United States, 341 U. S. 479, at 486-487; United States v. Burr, 25 Fed. Cas. 38, at 40-41, No. 14,692e. And see note 18, infra.
  Johnson v. Zerbst, 304 U. S. 458, 464. See also, e. g., Glasser v. United States, 315 U. S. 60, 70, and Smith v. United States, 337 U. S. 137, 150.
  Hoffman v. United States, 341 U. S. 479, 486-487. Compare the test laid down in Arndstein v. McCarthy, 254 U. S. 71, 72: “It is impossible to say from mere consideration of the questions propounded, in the light of the circumstances disclosed, that they could have been answered with entire impunity.” And see United States v. Coffey, 198 F. 2d 438, 440 (C. A. 3d Cir.): “It is enough (1) that the trial court be shown by argument how conceivably a prosecutor, building on the seemingly harmless answer, might proceed step by step to link the witness with some crime against the United States, and (2) that this suggested course and scheme of linkage not seem incredible in the circumstances of the particular case. It is in this latter connection, the credibility of the suggested connecting chain, that the reputation and known history of the witness may be significant.
  “Finally, in determining whether the witness really apprehends danger in answering a question, the judge cannot permit himself to be skeptical; rather must he be acutely aware that in the deviousness of crime and its detection incrimination may be approached and achieved by obscure and unlikely lines of inquiry.”
  United States v. Burr, 25 Fed. Cas. 38, at 40, No. 14,692e.
  Blau v. United States, 340 U. S. 159. See also Brunner v. United States, 343 U. S. 918, reversing 190 F. 2d 167 (C. A. 9th car.).
  In United States v. Singleton, 193 F. 2d 464 (C. A. 3d Cir.), the defendant was convicted of contempt for refusing to answer the question “What business is he in?” with respect to three named individuals. This Court summarily reversed, 343 U. S. 944, citing Hoffman v. United States, 341 U. S. 479, and Greenberg v. United States, 343 U. S. 918. The Hoffman decision, in reversing 185 F. 2d 617 (C. A. 3d Cir.), upheld an assertion of the privilege in response to questions concerning the whereabouts of an acquaintance of the defendant. The Greenberg decision, in reversing 192 F. 2d 201 (C. A. 3d Cir.), upheld an assertion of the privilege in response to a question, among others, asking the defendant to identify certain “men who are in the numbers business.” See note 24, infra.
  18 U. S. C. § 2385; 18 U. S. C. § 371.
  29 U. S. C. § 159 (h); 18 U. S. C. § 1001.
  At the present time the Courts of Appeals are apparently uniform in holding that the privilege may extend to questions of the sort involved here. See, e. g., Judge Learned Hand in United States v. Weisman, 111 F. 2d 260, 261 (C. A. 2d Cir.), upholding privilege in response to question of whether the witness knew anyone who visited, lived in, or stayed at, Shanghai in the years 1934 to 1939; Judge Augustus Hand in United States v. Zwillman, 108 F. 2d 802 (C. A. 2d Cir.), upholding privilege in response to question of who the witness’ business associates were in the years 1928 to 1932; Chief Judge Denman in Kasinowitz v. United States, 181 F. 2d 632 (C. A. 9th Cir.), upholding privilege in response to questions of whether the witness knew Dorothy Healy and whether the witness knew Dorothy Healy’s occupation; Chief Judge Magruder in Maffie v. United States, 209 F. 2d 225, 231 (C. A. 1st Cir.), upholding privilege in response to question, among others, whether witness knew “Specs” O’Keefe and Stanley Gusciora; Judge Holmes in Estes v. Potter, 183 F. 2d 865 (C. A. 5th Cir.), upholding privilege in response to question whether the witness personally knew a certain alien; Judge Rives in Marcello v. United States, 196 F. 2d 437, 442 (C. A. 5th Cir.), upholding privilege in response to question “Do you know Salvatore Vittali?”; Judge Martin in Aiuppa v. United States, 201 F. 2d 287 (C. A. 6th Cir.), upholding privilege in response to questions whether the witness knew R. L. O’Donnell and Anthony Aceardo; Judge Maris in In re Neff, 206 F. 2d 149 (C. A. 3d Cir.), upholding privilege in response to questions whether the witness knew Julius Zinman and Lou Malinow. See also Alexander v. United States, 181 F. 2d 480 (C. A. 9th Cir.); Doran v. United States, 181 F. 2d 489 (C. A. 9th Cir.); Healey v. United States, 186 F. 2d 164 (C. A. 9th Cir.); Poretto v. United States, 196 F. 2d 392, 396 (C. A. 5th Cir.); United States v. Girgenti, 197 F. 2d 218 (C. A. 3d Cir.) ; United States v. Coffey, 198 F. 2d 438 (C. A. 3d Cir.); Daly v. United States, 209 F. 2d 232, 233 (C. A. 1st Cir.). Cf. Kiewel v. United States, 204 F. 2d 1 (C. A. 8th Cir.); United States v. Doto, 205 F. 2d 416 (C. A.2d Cir.).