Spousal immunity (aka adverse testimony privilege) barred one spouse from testifying against the other. In most jurisdictions it applied only in criminal matters. The rule stemmed from the historical presumption that a defendant could not testify in his own behalf because of interest in the proceeding, and that because husband and wife were legally one entity, one spouse was incompetent to testify against the other.

It is now recognized that the accused has an unequivocal right to testify on his own behalf. Spousal immunity was therefore eliminated in Trammel v. United States, 445 U.S. 40 (1980) in those instances where the witness-spouse voluntarily waives immunity, although a reluctant spouse may not be compelled to testify. Thus in most jurisdictions nothing prevents a spouse from testifying voluntarily about circumstances concerning marital rape, but the spouse-witness-victim cannot generally be compelled to do so. However, courts have found exceptions to spousal immunity rules where the spouse is a victim of abuse and refuses to testify for fear of retribution or because the abuser coerces the victim.

In State v. Taylor, 642 So. 2d 160, 1994 La. LEXIS 1936 (1994), the Louisiana Supreme Court declined to recognize a severely battered victim's invocation of spousal immunity. The court wrote:

"[T]he dynamics of spousal abuse and domestic violence cannot be ignored. Fear, self-blame, and other emotional factors often leave a battered spouse unable to make a sound judgment as to whether to testify against an abusive spouse. Exercise of the spousal witness privilege may be the result of coercion, fear, subjugation, or undue influence, perhaps not even recognized by the abused spouse in some circumstances....

"[W]e…feel justified and even compelled to limit exercise of the privilege where facts and circumstances established by proper evidence indicate the privilege is being exercised because of fear, threats, or coercion…. We do not believe it was the legislative intent to make the privilege available under circumstances such as these where sanctity of the marriage and marital harmony are hardly served."

— Id. at 166.

The Supreme Court of Utah, in a 2009 marital rape case decision, declined to bar admission of a spouse’s out-of-court statements to police and to a Sexual Assault Nurse Examiner (SANE) respecting her husband’s attempt to force her to have anal and vaginal intercourse. Although the victim, at a preliminary hearing, refused to testify against her husband and was not compelled to do so, the Court did permit the State to introduce her out-of-court statements. The Court observed that the doctrine of spousal immunity prohibited only compelled, in-court testimony. Admission of spontaneous out-of-court statements was therefore not barred by the doctrine. The Court further acknowledged criticism of the doctrine as a vestige of the “unity”  doctrine, the fiction which presumed that husband and wife were legally inseparable. Moreover, the Court noted with concern that

“the privilege enables abusers to silence their victims and makes the testifying spouse vulnerable to coercion from the defendant-spouse and his lawyer. Amanda H. Frost, Updating the Marital Privileges: A Witness-Centered Rationale, 14 WIS. WOMEN’S L.J. 1, 23 (1999).”

State v. Timmerman, 2009 UT 58, 2009 Utah LEXIS 166 at *20

(Sept. 4, 2009).

In 2014, a Michigan Court of Appeals reversed the trial court’s grant of a motion to quash and dismissal of an indictment against the defendant, holding that the defendant’s wife was not vested with a spousal immunity under the applicable statute because the felony charges arose from defendant’s felony assault of his wife.  Accordingly, her consent to testify was not required and she could be compelled to testify against her husband.  People v. Szabo, 303 Mich. App. 737, 748-49, 846 N.W. 2d 412, 2014 Mich. App. LEXIS 140 at *16-17 (Jan.23, 2014), leave to appeal denied by, 497 Mich. 852, 2014 Mich. LEXIS 1529 (Sept. 5, 2014).