Ratzlaf (D) ran up a debt of $160,000 playing blackjack at the High Sierra Casino in Reno. D was given one week to pay and returned with $100,000 cash the next week. A casino official informed D that all transactions involving over $10,000 cash had to be reported to state and federal authorities. The official stated that cashier's checks for the full amount due but under $10,000 would not trigger the reporting requirement. D then went to local banks, bought cashier’s checks for under $10,000, and then gave the casino all the checks. D was charged with a structuring transaction under 31 U.S.C. §5324 and 5322. The first offense forbids purposefully structuring transactions in order to avoid reporting and the second required a mens rea of willfulness. The judge instructed the jury that the government had to prove D's knowledge of the banks' reporting obligations and his attempt to evade that obligation but did not have to prove that D knew that structuring was unlawful. D was convicted and appealed. The Court of Appeals confirmed.