MR. JUSTICE BLACK delivered the opinion of the Court.
Petitioner was convicted and sentenced to five years imprisonment by a United States District Court in Oklahoma on a charge that he violated the Mann Act, 18 U. S. C. § 2421, by transporting a girl from Arkansas to Oklahoma for immoral purposes. Over petitioner's objection the District Court permitted the Government
The common-law rule, accepted at an early date as controlling in this country, was that husband and wife were incompetent as witnesses for or against each other. The rule rested mainly on a desire to foster peace in the family and on a general unwillingness to use testimony of witnesses tempted by strong self-interest to testify falsely. Since a defendant was barred as a witness in his own behalf because of interest, it was quite natural to bar his spouse in view of the prevailing legal fiction that husband and wife were one person. See 1 Coke, Commentary upon Littleton (19th ed. 1832), 6. b. The rule yielded to exceptions in certain types of cases, however. Thus, this Court in Stein v. Bowman, 13 Pet. 209, while recognizing the "general rule that neither a husband nor wife can be a witness for or against the other," noted that the rule does not apply "where the husband commits an offence against the person of his wife." 13 Pet., at 221. But the Court emphasized that no exception left spouses free to testify for or against each other merely because they so desired. 13 Pet., at 223.
The Funk case, however, did not criticize the phase of the common-law rule which allowed either spouse to exclude adverse testimony by the other, but left this question open to further scrutiny. 290 U. S., at 373; Griffin v. United States, 336 U.S. 704, 714-715. More recently, Congress has confirmed the authority asserted by this Court in Funk to determine admissibility of evidence under the "principles of the common law as they
While the rule forbidding testimony of one spouse for the other was supported by reasons which time and changing legal practices had undermined, we are not prepared to say the same about the rule barring testimony of one spouse against the other. The basic reason the law has refused to pit wife against husband or husband against wife in a trial where life or liberty is at stake was a belief that such a policy was necessary to foster family peace, not only for the benefit of husband, wife and children, but for the benefit of the public as well. Such a belief has never been unreasonable and is not now. Moreover, it is difficult to see how family harmony is less disturbed by a wife's voluntary testimony against her husband than by her compelled testimony. In truth, it seems probable that much more bitterness would be engendered by voluntary testimony than by that which is compelled. But the Government argues that the fact a husband or wife testifies against the other voluntarily is strong indication that the marriage is already gone. Doubtless this is often true. But not all marital flare-ups in which one spouse wants to hurt the other are permanent. The widespread
Of course, cases can be pointed out in which this exclusionary rule has worked apparent injustice. But Congress or this Court, by decision or under its rule-making power, 18 U. S. C. § 3771, can change or modify the rule where circumstances or further experience dictates. In fact, specific changes have been made from time to time. Over the years the rule has evolved from the common-law absolute disqualification to a rule which bars the testimony of one spouse against the other unless both consent. See Stein v. Bowman, supra; Funk v. United States, supra; Benson v. United States, 146 U.S. 325, 331-333; United States v. Mitchell, 137 F.2d 1006, 1008. In 1887 Congress enabled either spouse to testify in prosecutions against the other for bigamy, polygamy or unlawful cohabitation. 24 Stat. 635. See Miles v. United States, 103 U.S. 304, 315-316. Similarly, in 1917, and again in 1952. Congress made wives and husbands competent to testify against each other in prosecutions for importing aliens for immoral purposes. 39 Stat. 878 (1917), re-enacted as 66 Stat. 230, 8 U. S. C. § 1328 (1952).
Other jurisdictions have been reluctant to do more than modify the rule. English statutes permit spouses to testify against each other in prosecutions for only certain types of crimes. See Evidence of Spouses in Criminal Cases, 99 Sol. J. 551. And most American States retain the rule, though many provide exceptions in some classes of cases.
Notwithstanding the error in admitting the wife's testimony, we are urged to affirm the conviction upon the alternative holding of the Court of Appeals that her evidence was harmless to petitioner. See Fed. Rules Crim. Proc., 52 (a). But after examining the record we cannot say that her testimony did not have substantial influence on the jury. See Kotteakos v. United States, 328 U.S. 750, 764-765. Interstate transportation of the prosecutrix between Arkansas and Oklahoma was conceded, and the only factual issue in the case was whether petitioner's dominant purpose in making the trip was to facilitate her practice of prostitution in Tulsa, Oklahoma.
MR. JUSTICE STEWART, concurring.
The rule of evidence we are here asked to re-examine has been called a "sentimental relic."
Any rule that impedes the discovery of truth in a court of law impedes as well the doing of justice. When such a rule is the product of a conceptualism long ago discarded, is universally criticized by scholars, and has been qualified or abandoned in many jurisdictions, it should receive the most careful scrutiny.
In the present case, however, the Government does not argue that this testimonial privilege should be wholly withdrawn. We are asked only to hold that the privilege is that of the witness and not the accused. Under such a rule the defendant in a criminal case could not prevent his wife from testifying against him, but she could not be compelled to do so.
A primary difficulty with the Government's contention is that this is hardly the case in which to advance it. A supplemental record filed subsequent to the oral argument
"Shall be fined not more than $5,000 or imprisoned not more than five years, or both."
In construing this Act, we have held: "The statute thus aims to penalize only those who use interstate commerce with a view toward accomplishing the unlawful purposes. . . . An intention that the women or girls shall engage in the conduct outlawed by § 2 must be found to exist before the conclusion of the interstate journey and must be the dominant motive of such interstate movement. And the transportation must be designed to bring about such result. Without that necessary intention and motivation, immoral conduct during or following the journey is insufficient to subject the transporter to the penalties of the Act.
". . . What Congress has outlawed by the Mann Act . . . is the use of interstate commerce as a calculated means for effectuating sexual immorality." Mortensen v. United States, 322 U.S. 369, 374-375. See Cleveland v. United States, 329 U.S. 14, 19-20. Cf. Hansen v. Haff, 291 U.S. 559, 563.
Before assuming that a change in the present rule would work such a wholesale disruption of domestic felicity as the Court's opinion implies, it would be helpful to know the experience in those jurisdictions where the rule has been abandoned or modified. It would be helpful also to have the benefit of the views of those in the federal system most qualified by actual experience with the operation of the present rule—the district judges and members of the practicing bar. The Judicial Conferences of the several Circuits would provide appropriate forums for imparting that kind of experience. 28 U. S. C. § 333.
It is obvious, however, that all the data necessary for an intelligent formulation "in the light of reason and experience" could never be provided in a single litigated case. This points to the wisdom of establishing a continuing body to study and recommend uniform rules of evidence for the federal courts, as proposed by at least two of the Circuit Judicial Conferences. See Annual Report of the Proceedings of the Judicial Conference of the United States, September 18-20, 1957, p. 43. See Joiner, Uniform Rules of Evidence for the Federal Courts. 20 F. R. D. 429.