A movement known as “tentherism” asserts that any U.S. state has the right to nullify, within the borders of that state, any federal law it deems unconstitutional. Tenthers base their argument on the 10th Amendment to the U.S. Constitution (hence the name “tenther”), which states: “The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.”

Supporters of tentherism include Texas Gov. Rick Perry and Sen. Jim DeMint (R-S.C.). In a statement on his website, Perry expresses “unwavering support for efforts all across our country to reaffirm the states’ rights affirmed by the Tenth Amendment to the U.S. Constitution.” DeMint is such a fan of the 10th that he tried to improve on it, claiming in an opinion piece for National Review (“Constitution of No,” June 8, 2010, available on DeMint’s website) that “the Tenth Amendment says powers not explicitly given to the federal government in the Constitution go to the states or the people.” (Italics mine. The actual 10th Amendment doesn’t use the word “explicitly.”)

The chief tenther organization is The 10th Amendment Center, which calls its 10th Amendment Movement “an effort to push back against unconstitutional federal laws and regulations on a state level. The principle is known as ‘nullification,’ and was advised by many prominent founders.”