Why did Lincoln refer to the right of each state to control its own affairs in his inaugural address

Lincoln gave his first inaugural address under the looming crisis of souther states seceding from the Union. At the time of the address in 1861 7 states had already declared secession and many feared the war was looming. In his address Lincoln made a major attempt to extend a hand of peace and compromise to the southern states in the hopes that the war could be avoided and that democratic principles could be used to resolve the issue. Therefore, the reference to the rights of states to resolve their own issues was very much a part of this effort to show that Lincoln wanted the southern states to remain part of the Union and that the federal government was not there to unilaterally impose its will on states in an undemocratic or unconstitutional fashion.