delivered the opinion of the Court.
Petitioner was tried and convicted of knowingly transporting a woman in interstate commerce for the purpose *526of prostitution, in violation of the White Slave Traffic Act, 18 U. S. C. § 2421. At the trial, the woman, who had since the date of the offense married the petitioner, was ordered, over her objection and that of the petitioner, to testify on behalf of the prosecution.1 The Court of Appeals, on appeal from a judgment of conviction, affirmed the ruling of the District Court. 263 F. 2d 304. As the case presented significant issues concerning the scope and nature of the privilege against adverse spousal testimony, treated last Term in Hawkins v. United States, 358 U. S. 74, we granted certiorari. 360 U. S. 908. We affirm the judgment.
First. Our decision in Hawkins established, for the federal courts, the continued validity of the common-law rule of evidence ordinarily permitting a party to exclude the adverse testimony of his or her spouse. However, as that case expressly acknowledged, the common law has long recognized an exception in the case of certain kinds of offenses committed by the party against his, spouse. Id., at 75, citing Stein v. Bowman, 13 Pet. 209, 221. Exploration of the precise breadth of this exception, a matter of some uncertainty, see 8 Wigmore, Evidence (3d ed.), § 2239, can await a case, where it is necessary. For present purposes it is enough to note that every Court of Appeals which has considered the specific question now holds that the exception, and not the rule, applies to a Mann Act prosecution, where the defendant’s wife was the victim of the offense.2 Such unanimity with respect *527to a rule of evidence lends weighty credentials to that view.
While this Court has never before decided the question, we now unhesitatingly approve the rule followed in five different Circuits. We need not embark upon an extended consideration of the asserted bases for the spousal privilege (see Hawkins, supra, at 77-78; Wigmore, op. cit., supra, § 2228 (3)) and an appraisal of the applicability of each here, id., § 2239, for it cannot be seriously argued that one who has committed this “shameless offense against wifehood,” id., at p. 257, should be permitted to prevent his wife from testifying to the crime by invoking an interest founded on the marital relation or the desire of the law to protect it. Petitioner’s attempt to prevent his wife from testifying, by invoking an asserted privilege of his own, was properly rejected.
Second. The witness-wife, however, did not testify willingly, but objected to being questioned by the prosecution, and gave evidence only upon the ruling of the District Court denying her- claimed privilege not to testify. We therefore consider the correctness of that ruling.3
*528The United States argues that, once having held, as we do, that in such a case as this the petitioner’s wife could not be prevented from testifying voluntarily, Hawkins establishes that she may be compelled to testify. For, it is said, that case specifically rejected any distinction between voluntary and compelled testimony. 358 U. S., at 77. This argument fails to take account of the setting of our decision in Hawkins. To say that a witness-spouse may be prevented from testifying voluntarily simply means that the party has a privilege to exclude the testimony ;4 when, on the other hand, the spouse may not be compelled to testify against her will, it is the witness who is accorded a privilege. In Hawkins, the Government took the position that the spousal privilege should be that of the witness, and not that of the party, so that while the wife could decline to testify, she could not be prevented from giving evidence if she elected not to claim a privilege which, it was said, belonged to her alone. Brief for the United States, No. 20, O. T. 1958, pp. 22-43. In declining to hold that the party had no privilege, we manifestly did not thereby repudiate the privilege of the witness.
While the question has not often arisen, it has apparently been generally assumed that the privilege resided in the witness as well as in the party. Hawkins referred to “a rule which bars the testimony of one spouse against the other unless both consent,” supra, at 78. (Emphasis supplied.) See Stein v. Bowman, supra, at 223 (wife cannot “by force of authority be compelled to state facts in evidence”); United States v. Mitchell, supra, at 1008 (“the better view is that the privilege is that of either spouse who chooses to claim it”); Wigmore, op. cit., supra, § 2241; McCormick, Evidence, § 66, n. 3. In its *529Hawkins brief, the Government, while calling for the abolition of the party’s privilege, urged that the common-law development could be explained, and its policies fully vindicated, by recognition of the privilege of the witness. Brief, pp. 22-25, 33, 42-43; see Hawkins, supra, at 77, and concurring opinion, at 82. At least some of the bases of the party’s privilege are in reason applicable to that of the witness. As Wigmore puts it, op. cit., supra, at p. 264: “[W]hile the defendant-husband is entitled to be protected against condemnation through the wife’s testimony, the witness-wife is also entitled to be protected against becoming the instrument of that condemnation, — the sentiment in each case being equal in degree and yet different in quality.” In light of these considerations, we decline to accept the view that the privilege is that of the party alone.
Third. Neither can we hold that, whenever the privilege is unavailable to the party, it is ipso facto lost to the witness as well. It is a question in each case, or in each category of cases, whether, in light of the reason which has led to a refusal to recognize the party’s privilege, the witness should be held compellable. Certainly, we would not be justified in laying down a general rule that both privileges stand or fall together. We turn instead to the particular situation at bar.
Where a man has prostituted his own wife, he has committed an offense against both her and the marital relation, and we have today affirmed the exception disabling him from excluding her testimony against him. It is suggested, however, that this exception has no application to the witness-wife when she chooses to remain silent. The exception to the party’s privilege, it is said, rests on the necessity of preventing the defendant from sealing his wife’s lips by his own unlawful act, see United States v. Mitchell, supra, at 1008-1009; Wigmore, op. cit., supra, § 2239, and it is argued that where the wife has chosen *530not to "become the instrument” of her husband’s downfall, it is her own privilege which is in question, and the reasons for according it to her in the first place are fully applicable.
We must view this position in light of the congressional' judgment and policy embodied in the Mann Act. "A primary purpose of the Mann Act was to protect women who were weak from men who were bad.” Denning v. United States, 247 F. 463, 465. It was in response to shocking revelations of subjugation of women too weak to resist that Congress acted. See H. R. Rep. No. 47, 61st Cong., 2d Sess., pp. 10-11. As the legislative history discloses, the Act reflects the supposition that the women with whom it sought to deal often had no independent will of their own, and embodies, in effect, the view that they must be protected against themselves. Compare 18 U. S. C. § 2422 (consent of woman immaterial in prosecution under that section). It is not for us to re-examine the basis of that supposition.
Applying the legislative judgment underlying the Act, we are led to hold it not an allowable choice for a prostituted witness-wife "voluntarily” to decide to protect her husband by declining to testify against him. For if a defendant can induce a woman, against her "will,” to enter a life of prostitution for his benefit — and the Act rests on the view that he can — by the same token it should be considered that he can, at least as easily, persuade one who has already fallen victim to his influence that she must also protect him. To make matters turn upon ad hoc inquiries into the actual state of mind of particular women, thereby encumbering Mann Act trials with a collateral issue of the greatest subtlety, is hardly an acceptable solution.
Fourth. What we have already said likewise governs the disposition of the petitioner’s reliance on the fact that his marriage took place after the commission of the *531offense. Again, we deal here only with a Mann Act prosecution, and intimate no view on the applicability of the privilege of either a party or a witness similarly circumstanced in other situations. The legislative assumption of lack of independent will applies as fully here. As the petitioner by his power over the witness could, as we have considered should be assumed, have secured her promise not to testify, so, it should be assumed, could he have induced her to go through a marriage ceremony with him, perhaps “in contemplation of evading justice by reason of the very rule which is now sought to be invoked.” United States v. Williams, 55 F. Supp. 375, 380.
The ruling of the District Court was correctly upheld by the Court of Appeals.5 .
Affirmed.
Although the record is ambiguous as to the fact and time of petitioner’s marriage, we shall consider established, as the Court of Appeals did, the sequence of events stated in the text. Further, the Court of Appeals noted that, while the record did not clearly establish that the petitioner, as well as his wife, claimed a privilege with respect to her testimony, it would assume that he had. 263 F. 2d 304, 308. We accept that assumption.
United States v. Mitchell, 137 F. 2d 1006 (C. A. 2d Cir.); Levine v. United States, 163 F. 2d 992 (C. A. 5th Cir.); Shores v. United *527States, 174 F. 2d 838 (C. A. 8th Cir.), overruling Johnson v. United States, 221 F. 250; Pappas v. United States, 241 F. 665 (C. A. 9th Cir.); Hayes v. United States, 168 F. 2d 996 (C. A. 10th Cir.).
The United States does not question the standing of petitioner to seek reversal because of the allegedly erroneous refusal to respect the privilege of his wife. Since such testimony, even if wrongly compelled, is per se admissible, Funk v. United States, 290 U. S. 371, and relevant, it has been argued that the party has suffered no injury of which he may complain. Wigmore, op. cit., supra, § 2196 (2) (a); McCormick, Evidence, §73; Uniform Rules of Evidence, Rule 40; Am. L. Inst. Model Code of Evidence, Rule 234; Note, 30 Col. L. Rev. 686, 693-694. See, e. g., Turner v. State, 60 Miss. 351,353. However, as the point has not been briefed or argued, we have thought it appropriate, in view of our disposition of the case on the merits, not to consider the issue of standing, and of course intimate no view on it.
Funk v. United States, supra, abolished, for the federal courts, the disqualification or incompetence of the spouse as a witness, thus establishing the admissibility of his or her testimony, and leaving the question one of privilege only.
The petitioner’s further assertion, that apart from the testimony of the wife there was insufficient corroboration of his admission of transportation, thus fails by its own assumption.