The United States Department of Energy regularly transports nuclear materials through Centerville on the way to a nuclear weapons processing plant it operates in a nearby state. The city of Centerville recently adopted an ordinance prohibiting the transportation of any nuclear materials in or through the city. The ordinance declares that its purpose is to protect the health and safety of the residents of that city. May the Department of Energy continue to transport these nuclear materials through the city of Centerville?
No, because the ordinance is rationally related to the public health and safety of Centerville residents.  No, because the Tenth Amendment reserves to the states certain unenumerated sovereign powers.  Yes, because the Department of Energy is a federal agency engaged in a lawful federal function and, therefore, its activities may not be regulated by a local government without the consent of Congress.  Yes, because the ordinance enacted by Centerville is invalid because it denies persons transporting such materials the equal protection of the laws. 