James Buchanan had been a candidate for president at the 1852 Democratic National Convention , and after the 1852 election he agreed to serve as Pierce 's ambassador to Britain . Buchanan 's service abroad conveniently placed him outside of the country while the debate over the Kansas – Nebraska Act roiled the nation . Powerful Senators like John Slidell , Jesse Bright , and Thomas F. Bayard lined up behind Buchanan , presenting him as an experienced leader who could appeal to the North and South . While Buchanan did not overtly seek the presidency , he most deliberately chose not to discourage the movement on his behalf , something that was well within his power on many occasions
1852 Democratic National Convention
1852 Democratic National Convention
1856 Democratic National Convention