What was a failed attempt by congress to settle the slavery issue as southern states started seceding from the union?

One notable failed attempt by Congress to address the slavery issue during the secession crisis was the Crittenden Compromise in late 1860. Proposed by Senator John J. Crittenden, it sought to extend the Missouri Compromise line westward and ensure the protection of slavery in southern territories. However, the proposal failed to gain enough support, particularly from Republican lawmakers who opposed the expansion of slavery, ultimately contributing to the deepening divide that led to the Civil War.