I’ve been writing about nullification for years. Nullification, in short, is the principle that any law passed without proper authority is not a valid law and is not enforceable on the people. In the US, the Constitution carefully defines the authority the federal government and acknowledges that whatever powers were not delegated expressly to the government are reserved by the states. Article VI, Section 2 (the Supremacy Clause) states that the Constitution and all laws passed in pursuance to it are supreme law. The reverse is therefore implied and true – that all laws NOT passed in pursuance to powers delegated by the Constitution are not supreme. The states therefore have no obligation to recognize or enforce them.