In the 1910 case of Wilson v. United States, the Supreme Court ruled that a defendant's wife could testify against him in court. The case involved a man named James Wilson who was convicted of bigamy after his first wife testified against him during trial. On appeal, he argued that under common law principles and federal statutes, his wife should not have been allowed to provide testimony as it violated marital privilege rules which protect confidential communications between spouses from disclosure in court proceedings. However, the Supreme Court disagreed with this argument stating that while there is indeed such a rule protecting private conversations between husband and wife from being disclosed without consent from both parties; it does not extend to prevent one spouse from testifying about facts or events occurring outside those privileged communications when they are called upon by courts to do so.

In the dissenting opinion for Wilson v. United States, Justice Harlan argued that the majority's decision was a misinterpretation of the Fifth Amendment. He believed that compelling a defendant to produce private papers against himself in court violated his constitutional right against self-incrimination. According to him, this principle should apply regardless of whether or not these documents contained incriminating evidence because it is about protecting personal privacy and security from government intrusion. Furthermore, he contended that if such an invasion were allowed under law, it would lead to potential abuses by those in power who could use this as a tool for oppression and intimidation against citizens they deemed undesirable or threatening.