Defendant bears the burden of proving a defense of withdrawal from a conspiracy

Smith v. United States, No. 11-8976 (U.S. Jan. 9, 2013) (Scalia, unanimous)

Since Congress did not assign the Government the burden of proving the nonexistence of withdrawal, the Court presumes that Congress wanted to preserve the common-law rule that the defendant must prove affirmative defenses.  Withdrawal does not negate an element of the charged conspiracy, and the Government does not have to prove that all affirmative defenses do not exist.  Affirms conspiracy convictions under jury charge that once the Government proved defendant was a member of a conspiracy, defendant has to prove withdrawal from a conspiracy by a preponderance of the evidence.