common definition of robbery in §§ 2111, 2113, and 2118, thereby bringing those state convictions within § 3559(c)(2)(F)(i). See supra at 144. Insofar as § 3559(c)(3)(A) afforded Snype an opportunity to avoid imposition of a lifetime sentence on a clear and convincing showing of specified circumstances, we conclude that no Sixth Amendment concern arises because, as previously observed, § 3559(c)(3)(A) can be analogized to a safety valve or an affirmative defense, which is properly considered only after a court determines that the defendant’s present and past convictions constitute serious violent felonies under § 3559(c)(2)(F)®, thereby triggering the sentencing mandate of § 3559(c)(1). See generally Patterson v. New York, 432 U.S. 197, 205-06, 209, 97 S.Ct. 2319, 53 L.Ed.2d 281 (1977) (<HOLDING>); United States v. Holguin, 436 F.3d at 117
holding that apprendi leaves undisturbed the principle that while the prosecution must indeed prove all the elements of the offense charged beyond a reasonable doubt the legislation creating the offense can place the burden of proving affirmative defenses on the defendant internal citations omitted recognizing congresss power to place burden of proving affirmative defense on defendant as long as state proves all elements of the crime beyond a reasonable doubt recognizing that federal preemption is affirmative defense as to which defendant has burden of proof holding that conviction of a crime requires proof beyond a reasonable doubt of every fact necessary to constitute the crime holding the trial court erred in not charging the jury that a defendant had the burden of proving the affirmative defense of comparative negligence