The theory of nullification claims the states have the power to declare federal laws unconstitutional. This idea was first introduced in the Kentucky and Virginia resolutions in response to the Alien and Sedition Acts. Several states maintained the Alien and Sedition Acts were unconstitutional, so they had the power to nullify that statute within the jurisdiction of the particular states.
Nullification refers to a state law declaring one or more federal laws void within the boundaries of the state. The state may or may not make the nullification ordinance conditional. It may or may not impose criminal or civil penalties on persons attempting to enforce the nullified law.
Rob Natelson, a senior fellow of The Heartland Institute, is a leading scholar on constitutional reform matters generally and nullification specifically. In a Policy Study for Heartland, he explains:
the doctrine of nullification was not recognized, directly or indirectly, either by the Constitution or by any of the state conventions that ratified it. The idea that nullification is a constitutional remedy originated in the Kentucky Resolutions. These were adopted in 1798, several years after the ratification. Their author was Thomas Jefferson. Although Jefferson was certainly a leading Founder, his political and constitutional views were outside the American mainstream. In addition, he had not been involved personally in the ratification debates, because he was in France at the time. In any event, seven of the remaining 14 states passed responsive resolutions rejecting the notion that individual states could act as final authority on the constitutionality of federal laws.
In contrast to Jefferson, Madison was within the political mainstream and had been a leading framer and ratifier of the Constitution. His Virginia Resolution promoted interposition rather than nullification. He later denied that nullification was a constitutional remedy, and his view has become accepted constitutional law.
As The Federalist No. 46 makes clear, however, Madison did agree that under certain circumstances the people have the natural right to revolt against a government and establish another. As noted earlier, he believed such extraconstitutional steps should be reserved until all constitutional remedies had been exhausted.
Nullification is the state-law analogue of revolution. In the extreme conditions justifying revolution, resistance need not be conducted solely by private individuals or groups. States may participate officially, as the colonies/states did during the years 1775–83. This is the scenario Madison presented in The Federalist No. 46. Obviously, in these circumstances a state may declare federal law void within its boundaries.
Nullification ultimately depends on military power for its force. Like other revolutionary methods, it is effective only if federal authorities do not have the will or power to overcome state resistance.
As Natelson wrote in a February 3, 2014 article, “Struggling with Nullifcation,”
Once the pure state compact theory falls, it is very hard to justify nullification (narrowly defined) as a constitutional remedy. It remains instead a remedy reserved by natural law for when the Constitution has wholly failed—in other words, in situations justifying revolution.