In one of the first published decisions from the October session, the Supreme Court issued a short but interesting opinion concerning conspiracy charges. Typically, when a criminal defendant has been charged with conspiracy, the burden of proof falls to the prosecutor to show that there was, in fact, a conspiracy.
That said, the court answered a question in Smith v. United States as to who bears the burden of proof if the defendant demonstrates some proof as to their withdrawal from a conspiracy outside of the scope of the statute of limitations. The petitioner, Smith, argued that once some proof has been submitted to suggest that the defendant had withdrawn from the conspiracy, the burden shifted to the prosecution. The court, however, disagreed.
Justice Scalia, in writing for the court, stated "this position draws support neither from the Constitution (as discussed in this Part II), nor from the conspiracy and limitations statutes at issue…" He continued, "While the Government must prove beyond a reasonable doubt every fact necessary to constitute the crime with which [the defendant] is charged,' In re Winship, 397 U. S. 358, 364 (1970), proof of the nonexistence of all affirmative defenses has never been constitutionally required.
Citations: Smith v. United States, No. 11–8976 (S. Ct. Jan. 9, 2013)