Slidell was elected to the Senate in 1853 and cast his lot with other pro-Southern congressmen to repeal the Missouri Compromise , acquire Cuba , and admit Kansas as a slave state . In the 1860 campaign Slidell supported Democratic presidential candidate John C. Breckinridge , but remained a pro-Union moderate until Abraham Lincoln 's election resulted in the Southern states seceding . At the Democratic National Convention in Charleston , South Carolina , in April 1860 , Slidell plotted with " Fire-Eaters " such as William Lowndes Yancey of Alabama to stymie the nomination of the popular Northern Democratic Senator Stephen A. Douglas of Illinois
Democratic National Convention
1860 Democratic National Conventions
John Slidell