Which President attempted to balance pro-slavery and anti-slavery factions but ultimately failed?

James Buchanan's presidency (1857-1861) was marked by significant tension between pro-slavery and anti-slavery factions, largely due to the divisions within the country surrounding the issue of slavery. He sought to maintain a precarious balance between the two sides, believing that compromise was the best path toward preserving the Union. His support for the controversial Kansas-Nebraska Act and his endorsement of the pro-slavery Lecompton Constitution in Kansas exemplify his attempts to satisfy Southern interests while also appeasing Northern anti-slavery sentiments.

However, Buchanan's efforts to manage the divisions ultimately failed, as they alienated both sides. He was unable to secure support for the Lecompton Constitution, leading to increased polarization. His presidency was characterized by the inability to effectively address the deepening crisis over slavery, contributing to the conditions that led to the Civil War. Therefore, he stands out as the president who most visibly grappled with the challenge of balancing these competing factions but did so unsuccessfully.