Carol Anne Bond (defendant) learned that her husband had impregnated one of her friends. Bond sought revenge by placing toxic chemicals on the friend’s mailbox, car-door handle, and doorknob. The friend burned her hand after touching the chemicals. Bond was charged in federal court with violating 18 U.S.C. § 229, a federal statute that prohibits the knowing possession or use of a chemical that can kill, permanently injure, or temporarily incapacitate humans or animals. Congress enacted the statute as part of implementing an international chemical-weapons treaty that the United States ratified in 1997. Bond moved to dismiss the charges, asserting that Congress did not have the constitutional authority to enact the statute. The district court denied Bond’s motion, and she pleaded guilty on the condition that she could challenge the statute on appeal. In her appeal, Bond challenged the statute under the Tenth Amendment to the United States Constitution, arguing that Congress could not enact the statute under its enumerated powers. The United States (plaintiff) argued that Bond did not have standing to assert a Tenth Amendment violation. The court of appeals agreed with the government and held that Bond did not have standing to challenge the statute on Tenth Amendment grounds because a state was not participating in the action. The United States Supreme Court granted certiorari. The government subsequently changed its position and agreed that Bond had standing to challenge the statute. The Supreme Court appointed a lawyer to defend the appellate court’s position as an amicus curiae. The amicus argued that only states may assert a Tenth Amendment claim that a federal statute interferes with the rights reserved to the states.