I filed a motion to quash not too long ago in a federal criminal case, where the Government was seeking to have the defendant's husband testify against her. In federal law cases, testimonial privileges are determinined under the federal common law. In Trammel v. United States, the Supreme Court held that the adverse spousal testimony privilege would continue to be recognized, but limited the privilege to be asserted by the witness and not the defendant.
In criminal cases arising under Virginia law, the corresponding privilege is found in Va. Code 19.2-271.2, which begins: "In criminal cases husband and wife shall be allowed,
and, subject to the rules of evidence governing other witnesses, may be
compelled to testify in behalf of each other, but neither shall be
compelled to be called as a witness against the other."