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1856 election
Main article: 1856 Democratic National Convention
Partisan violence spilled into Congress in May 1856 when Free Soil Senator Charles Sumner was assaulted with a walking cane by Democratic Rep. Preston Brooks in the Senate chamber.[137]
Pierce fully expected to be renominated by the Democrats. In reality, his chances of winning the nomination (let alone the general election) were slim. The administration was widely disliked in the North for its position on the Kansas–Nebraska Act, and Democratic leaders were aware of Pierce's electoral vulnerability. Nevertheless, his supporters began to plan for an alliance with Douglas to deny James Buchanan the nomination. Buchanan had solid political connections and had been safely overseas through most of Pierce's term, leaving him untainted by the Kansas debacle.[138][139][140]
When balloting began on June 5 at the convention in Cincinnati, Ohio, Pierce expected a plurality, if not the required two-thirds majority. On the first ballot, he received only 122 votes, many of them from the South, to Buchanan's 135, with Douglas and Cass receiving the rest. By the following morning fourteen ballots had been completed, but none of the three main candidates were able to get two-thirds of the vote. 