Cooper v. Aaron: Striking down nullification, again

In 1958, in Cooper v. Aaron, the Supreme Court, ensnared in the white-hot cauldron of southern resistance to federal authority, the Supremacy Clause and the abolition of segregation, delivered a massively important decision for the future of American Constitutionalism and the rule of law.

In a case that threatened the very existence of the United States as a nation, the court reiterated its role a...