involvement with five or more kilograms of cocaine, arguing that he had withdrawn before El Don organized the delivery of the intercepted 7.2 kilograms of cocaine on March 25, 2011. Ortega argues that the sole evidence of a conspiracy existing at the time of the seizure of 7.2 kilograms of cocaine on March 25, 2011 was the April 17, 2011 phone calls between Ortega and El Don. In that call Ortega had arranged for El Don to buy five kilograms of cocaine. Ortega’s argument is unavailing. A conspiracy between Ortega and El Don having been established by the government, the burden rested with Ortega to prove that he affirmatively withdrew from it, not with the government to prove the nonexistence of withdrawal. See Smith v. United States, — U.S. -, 133 S.Ct. 714, 720, 184 L.Ed.2d 570 (2013) (<HOLDING>). We conclude that Ortega has not met his
holding that in passing 21 usc  846 congress left the common law burden of proving the affirmative defense of withdrawal on the defendant rather than requiring the government to prove nonexistence of withdrawal holding that the government was not responsible for delay from withdrawal of guilty plea holding that the defendant has the burden of proving a fair and just reason for withdrawal of a guilty plea holding that defendant was responsible for the delay from the withdrawal of his guilty plea holding that when congress is silent on the issue of the burden of proof applicable to a common law affirmative defense that does not negate an element of the offense we presume congress intended the defendant to bear the burden of proof of the defense by a preponderance of the evidence