James Buchanan

Historians criticize Buchanan for his inability to ease tensions over slavery and for political choices—such as endorsing the Dred Scott decision and supporting the pro‑slave Lecompton Constitution—that deepened sectional division. His administration's reluctance to use federal authority or build durable compromise is widely seen as contributing to the collapse of national consensus and the outbreak of the Civil War.

Before the presidency Buchanan had a long career as a congressman, U.S. senator, Secretary of State, and minister to Great Britain, where he was respected for his diplomatic experience. His record raises enduring questions about presidential leadership in crisis; modern rankings often place him among the least effective presidents because his policies failed to avert disunion.

15th U.S. President (1857–1861); Endorsed the Dred Scott decision and supported the pro‑slave Lecompton Constitution for Kansas; Long diplomatic career as U.S. minister to the United Kingdom and Secretary of State; Sought legal and diplomatic measures to preserve the Union but failed to prevent secession; Sent a relief expedition to Fort Sumter in 1861