In a criminal trial the spouse of the defendant has a privilege not to testify at the trial of the defendant or the defendant has a privilege to prevent a spouse from testifying. This privilege is called, variously, the marital privilege, the marital testimony privilege, or the adverse spousal testimony privilege.

Chambers v. Mississippi, 410 U.S. 284, pin? (1973).The Compulsory Process Clause of the Sixth Amendment to the U.S. Constitution grants a criminal defendant the right to introduce exculpatory evidence that is probative of and relevant to a material issue.

United States v. Anderson, 303 F.3d 847, 859 (7th Cir. 2002) (upholding trial court's admission of testimony about witnesses' statements to law enforcement officers which identified defendant as their drug supplier....A prior statement of a witness is exempt from the prohibition against hearsay evidence if the prior statement is consistent with the witness' testimony at the trial or hearing at which the prior statement is offered, the prior statement is offered to rebut a express or implied charge of recent fabrication or motive, and the witness who made the prior statement testifies and is subject to cross-examination at the trial or hearing at which the prior statement is offered.

Crawford v. Washington, 541 U.S. 36, 56 (2004) ("Most of the hearsay exceptions covered statements that by their nature were not testimonial--for example, ... statements in furtherance of a conspiracy.").If a statement is offered against a criminal defendant as the statement of the defendant's co-conspirator which was made during and in furtherance, the statement is not a "testimonial" statement for purposes of the right of confrontation guaranteed by the Sixth Amendment of the United States Constitution and the statement is therefore not subject to the constraints on admissibility imposed by that confrontation right on "testimonial" hearsay statements.