Why did Douglas lose southern support?

Stephen A. Douglas lost southern support primarily due to his stance on popular sovereignty, which allowed territories to decide for themselves whether to permit slavery. His support for the Kansas-Nebraska Act, which effectively repealed the Missouri Compromise, angered many in the South who felt he was not sufficiently committed to the expansion of slavery. Additionally, Douglas's opposition to the Lecompton Constitution, which sought to admit Kansas as a slave state, alienated him from Southern Democrats who viewed his actions as a betrayal of their interests. This shift contributed to his decline in favor among Southern voters.