Which senator backed a last-ditch effort to forge a compromise between the north and the south in early 1861?

John Crittenden tried to find a way for the two sides to compromise just before the Civil War broke out. The compromise would have prohibited slavery from any new territories north of the 36° 30′ parallel (the southern border of Missouri), and guaranteed it in any states formed south of it. In addition, it would have made the Fugitive Slave Act permanent and executable in all the new states and territories.