http://thinkprogress.org/justice/2014/10/03/3575875/frontrunner-in-iowa-senate-race-said-federal-officials-should-be-arrested-for-implementing-obamacare/
"Nullification is the unconstitutional theory that a state can unilaterally invalidate a federal law and cause it to cease functioning within the state’s borders. This theory directly at odds with the text of the Constitution, which provides that duly enacted federal laws “shall be the supreme law of the land; and the judges in every state shall be bound thereby, anything in the constitution or laws of any state to the contrary notwithstanding.” As James Madison noted in 1830, nullification would “speedily put an end to the Union itself” if it were ever accepted because it would render every single act of Congress optional.
Nevertheless, the concept of nullification enjoyed a bit of a renaissance among tea party activists shortly after President Obama took office."
