This was the only time in U.S. history in which a political party denied renomination to the incumbent president and won. Incumbent Democratic President Franklin Pierce was widely unpopular in the North because of his support for the pro-slavery faction in the ongoing civil war in territorial Kansas, and Buchanan defeated Pierce at the 1856 Democratic National Convention. Buchanan, a former Secretary of State, had avoided the divisive debates over the Kansas–Nebraska Act by virtue of his service as the Ambassador to the United Kingdom.