What is Franklin Pierce's legacy?

Franklin Pierce's legacy was one of growing division within the United States, between slave state and free state. As a Northern Democrat, Pierce came to see the abolitionist movement as the biggest single threat to the stability of the Union. Far from recognizing the limitless capacity of slavery to tear the country apart, not to mention its inherent wickedness, Pierce attempted to facilitate the institution's expansion into the new territories of Kansas and Nebraska.
The notorious Kansas-Nebraska Act of 1854, signed into law by President Pierce, was supposed to allow the people who lived in these territories to decide whether they would allow slavery within their boundaries. But in Kansas—"Bleeding Kansas" as it soon became known—this simply led to widespread political chaos and outbreaks of violent civil disorder, as each side accused the other of electoral fraud. Pierce, supposedly a supporter of states's rights, had no hesitation in sending in a detachment of Federal troops to quell the growing violence as well as forcibly dissolving the anti-slavery legislature.
Pierce's blatant partiality towards pro-slavery forces during his time in office created a lot of bad blood, which in turn drove North and South further apart than ever and hastened the nation's slide towards civil war.