One of the most well-settled questions in US constitutional law is that duly enacted federal laws overcome all state laws that conflict with them‚ and that states may not prevent federal officials from performing their official job duties. This principle is written into the Constitution itself‚ which provides that federal law “shall be the supreme law of the land; and the judges in every state shall be bound thereby.” The Supreme Court has even held‚ in In re Neagle (1890...