A House Divided

Abraham Lincoln's House Divided speech drew clear lines between Democrats and Republicans as the 1858 U.S. Senate campaign in Illinois got underway.

Sources used:

Blumenthal, Sidney: All The Powers of Earth. Simon and Schuster, 2019.
 
Burlingame, Michael, Abraham Lincoln: A Life. (Vol. 1). The John Hopkins University Press, 1995.

Collected Works of Abraham Lincoln. 1953 Edition hosted by the University of Michigan.

Davis, Rodney and Wilson, Douglas, ed. Herndon's Informants: Letters, Interviews, and Statements about Abraham Lincoln. University of Chicago Press, 1998.
 
Davis, Rodney and Wilson, Douglas, ed. Herndon on Lincoln: Letters. Knox College Lincoln Studies Center, 2016.

Donald, David Herbert, Lincoln: A Biography. Simon and Schuster, 1995.

Finkleman, Paul, Dred Scott v. Sandford: A Brief History with Documents. Bedford Books, 1997.

Foner, Eric, The Fiery Trial:  Abraham Lincoln and American Slavery. W.W. Norton and Company, 2011.

Guelzo, Alan, Lincoln and Douglas: The Debates That Defined America. Simon and Schuster, 2008.