Whether a defendant can be convicted and subjected to enhanced punishment under 21 U.S.C. § 841 without proof that he knew the drug type and quantity

QUESTION PRESENTED Whether, under 21 U.S.C. § 841, a defendant who knowingly possesses or distributes a controlled substance can be convicted and subjected to an enhanced Punishment on the basis of drug type and quantity in the absence of proof that he knew that he possessed that drug type and/or quantity? 1