Under Emmer's proposal, no federal mandate upon the state would be honored by Minnesota unless the governor, Speaker of the state House and state Senate Majority Leader were to issue determinations that the federal government has the power to legislate in that area. If any of those three officials were to determine that the federal government does not have the relevant power, the mandate could not take effect unless the legislature passed a law specifically applying it.
MinnPost pointed out to Emmer that this idea runs afoul of the Supremacy Clause of the Constitution, which established that federal laws are the "supreme Law of the Land" to which states are bound. It was only noted that Emmer's method skips the traditionally accepted manner for states to challenge a federal law, to file a lawsuit and adjudicate the matter in the courts. Emmer responded that this is the "preferred mechanism by some. That is usually federal-leaning constitutionalists." But he said the states shouldn't wait for courts to determine the scope of the federal government's authority.
"So while I appreciate that some might say that is the mechanism, well, that is one of the mechanisms," said Emmer. "I think if you're going to talk about a constitutional legal question. I'm taking about taking it from whether or not the authority is there in the first place. [Meaning the constitutional authority for the federal government to legislate in a particular area]. The state certainly does have the right to determine that at the state level, I believe, under our existing constitution."
It should be noted that theories of nullification were often floated during the first several decades of the United States, by individual states having disputes with the federal government over issues ranging from slavery to tariffs -- but the Civil War and the Northern victory over Southern secession firmly established the supremacy of the federal government. Nullification was later invoked by Southern segregationists during the Civil Rights movement, and was consistently rejected in federal courts.