What went wrong during Franklin Pierce's presidency?

Franklin Pierce (1804–69) was the 14th President of the United States (1853–57). A great deal went wrong during his presidency: personal grief, foreign policy missteps, and bitter sectional disputes.
In 1852, the Democrats had a difficult time selecting a candidate for the presidential election. Pierce was a "dark horse" candidate who won the nomination on the 49th ballot. In the general election, he defeated Winfield Scott, his commander during the Mexican War.
Prior to becoming president, Pierce had had an unremarkable career in New Hampshire state politics and in both the US House of Representatives and Senate. He was charismatic and gregarious, but he sometimes drank too much.
A few weeks before his inauguration, his only surviving son died in a terrible train accident. He and his wife witnessed the tragedy and were—not surprisingly—emotionally scarred.
In foreign policy, Pierce alienated many Northerners by wanting to annex Cuba and by supporting aggressive policies in Central America. The North did not want to take Cuba, knowing that it would almost certainly become a slave state. In Nicaragua, Pierce's aggressive policies included bombardment of a British protectorate and support for William Walker's adventurism.
The North-South dispute was intense during his presidency. Pierce secured the Gadsden Purchase and wanted to develop the West. But the Kansas-Nebraska Act of 1854 made him extremely unpopular in the North. This measure enabled slavery to expand in territories where it had previously been barred. Pierce was excoriated by his own party and denied renomination for the presidency.
Pierce's final years were not happy ones. His opposition to Abraham Lincoln earned him many enemies. He took up drinking again and faded into obscurity.