South Carolina, led by former Vice President John C. Calhoun, had threatened to secede from the union over an individual state's ability to void federal tariffs. The tariffs were put in place by Henry Clay and his political allies, and they favored the growing industrial north over the slave-dependent exports of the south. In response to South Carolina's threats, Jackson threatened to march the U.S. Army into the state and hang any man he deemed treasonous, and Congress approved a bill allowing the president to use force to enforce the law.