Final answer:
President Buchanan's response to the secession crisis was largely ineffective and contributed to the deepening of sectional tensions. The Dred Scott decision and support for the Lecompton Constitution angered anti-slavery northerners and fueled the secession crisis.
Step-by-step explanation:
President James Buchanan's response to the secession crisis was largely ineffective and contributed to the deepening of sectional tensions. The Dred Scott decision, which ruled that black Americans could not be citizens and upheld the rights of slave owners, was seen as favoring the South and further angered anti-slavery northerners.
Buchanan also supported the Lecompton Constitution, a pro-slavery document rejected by the majority of Kansans, which undermined his credibility and further fueled the secession crisis. Ultimately, Buchanan's attempts to appease the South and avoid secession failed, and several southern states seceded from the Union shortly after his presidency ended.