The Texas Tribune has an article about the rally which looks at the background of nullification. The group New Revolution Now promoted the rally.
The Virginia and Kentucky Resolutions are often a point of reference for nullifiers, but John C. Calhoun was the primary exponent of this doctrine, which was carried out by South Carolina in 1832 in response to tariffs passed by the United State Congress.In 1832, President Andrew Jackson issued a proclamation expressing his opinion on the constitutionality of the Nullification Ordinance of South Carolina. Further discussion of the constitutionality of nullification can be found in another work from 1832: Strictures on nullification.
However, the Nullification Crisis of 1832 was not the only instance of nullification. According to Edward Payson Powell, in Nullification and Secession in the United States (published in 1897), the New England states attempted to nullify federal acts during the War of 1812:
The Supreme Court of Massachusetts affirmed that the States had a right to decide whether exigencies existed that warranted the calling forth of the militia. This meant that any governor could nullify a declaration of war by the national government, and could refuse to furnish troops.In the Nullification Crisis of 1832 and the call for nullification of "Obamacare," the claim is that the acts are unconstitutional, but is nullification the correct procedure, or even the legal channel, to challenge an act of Congress? If one state nullifies an act as unconstitutional, it does not void the act in other states, and thus that act is still the law of the land in those states. One would have to conclude that if an act is so blatantly unconstitutional, then it can be challenged in court, otherwise, it is the supreme law of the land and must be followed, since the Constitution and all federal laws made within it's purview trump state law.