Franklin Pierce was so good looking, guys. A real charmer. Adored by everyone, a favorite at Bowdoin, and successful in business. Peter Wallner, his biographer, trots out testimony after testimony of how nice, gentlemanly, and smart he was. Probably because, to look at his presidency, you would conclude that he had his head in his pants.
A protege of Daniel Webster, he served in the House, Senate, and was a brigadier general in the Mexican American War. Then his wife, Jane, who was sickly, religious, and shy, made him leave politics and move back to New Hampshire to raise their three kids. Which he did.
Because also, he was an alcoholic. And politics made him hit the bottle. So he spent ten lovely years in New Hampshire with his wife and kids, staying sober.
Then the convention of 1852 came along, and the Democrats could not decide between Stephen Douglas, William Marcy, James Buchanan, and Lewis Cass. Thirty-four ballots went by, and no one would change their vote. Finally, someone said, "Hey, remember Franklin Pierce, he used to be a Senator?" "No," all the delegates replied. "Well, he is good looking and friends with Daniel Webster." "Ok, let's make him our candidate."
Candidate he was, and he easily beat Winfield Scott in the presidential election, because people in general were tired of Winfield Scott running for president.
What Franklin Pierce believed in was small, efficient government that neither aided nor hindered people from doing their own thing. As such, he vetoed a bill full of mental health treatment reforms, because it would have given public land for new mental institutions. (He was, however, an extremely good administrator. Never had the federal government been run so smoothly, they all said.)
But any chance he had of being remembered well was brought down by Kansas and Nebraska. It all started when they wanted to build a railroad to the Pacific. To do so, they had to formalize Nebraska as a territory. To do that, they had to decide whether or not to allow slavery in Nebraksa.
Actually, they didn't have to decide - the Missouri Compromise prohibited slavery in the Nebraska territory, but a handful of Southern senators got together and refused to vote for a territorial bill unless slavery was explicitly allowed. Stephen Douglas, a big proponent of both territories and railroads, rewrote the bill to include popular sovereignty - the provision that allows a new territory or state to decide for themselves whether or not to allow slavery.
This wasn't enough for the South. They wanted an official repeal of the Missouri Compromise, not just a new bill that ignored it. Franklin Pierce was just the man for the job. He believe in states' rights almost as much as the South did, and he agreed to repeal the Missouri Compromise on those grounds. This emboldened the South, and infuriated the North. It's safe to say that, while the Civil War had been building steam for almost a century, no single act provoked it as directly as Pierce's compromise.
He became very unpopular, and wasn't renominated for a second term. During Buchanan's administration, he and Jane traveled around Europe, hanging out with Nathaniel and Sophie Hawthorne. Soon after they returned to the States, Jane and Nathaniel - essentially Pierce's two best friends - both died, and Frank started drinking again. He spent his last years getting drunk and bad-mouthing Lincoln. He was against Lincoln and reunification until the end, stubbornly demanding that personal liberty laws made the Civil War unconstitutional.
He was the wrong president at the wrong time. In a less polarizing era he could have been a good president, with his powers of persuasion and knack for detail. In the 1850s, he just made things worse.