Stephen douglas did all of the following in his debates with abraham lincoln except which one? a. he promoted his popular sovereignty idea . b. he attacked lincoln's “a house divided” statement. c. he claimed that the declaration of independence was written by white men for white men. d. he agreed with lincoln on the point that slavery should be contained to where it already existed.

I think the answer is  D. He agreed with Lincoln on the point that slavery should be contained to where it already existed.
Stephen douglass heavily disagree with lincoln on this point. As a promoter of popular sovereignty, Douglass believed that The majority of people on the states should decide what to do with slavery. According to him, If they wanted to extended the slavery, they could

Political forces often influence public opinion.