First, the federal drug law explicitly immunizes state officials from prosecution for conduct while enforcing any state drug law. Second, unlike the federal lawsuit against Arizona over immigration, no U.S. attorney, Mr. Oberly included, has ever challenged any state's medical marijuana law in court. So there is no judicial or statutory authority for these threats. Mr. Oberly's letter does not refer to any statute, any court ruling or any constitutional provision challenging the Delaware law. Very simply, Mr. Oberly gambled his empty threat would scare Mr. Markell, and it worked.