Robert W. Johannsen writes a biography of Stephen A. Douglas focusing on his political career in the 1850s.
Robert W. Johannsen, The Frontier, The Union, and Stephen A. Douglas (Urbana: University of Illinois Press, 1989)
[from the cover]
In the 1850s, American political thought was dominated by concerns over the issues of slavery, secession, and the nature of the Union. The fifteen essays in this collection, including two previously unpublished pieces, discuss these concerns as they were reflected on the western frontier, in the ideas and actions of Stephen A. Douglas and Abraham Lincoln, and the cultural perceptions of mid-nineteenth century America.