We have a pretty good idea from Harry Jaffa's two books.
Your deduciton is ludicrous. It was just such open borders that eventually precipitated the Civil War. Bleeding Kansas resulted from letting anyone come in ,call themself a Kansan,vote for slavery and then LEAVE
Treason was what Douglas did, if anything was.
Douglas’s offenses? He inherited a Mississippi plantation, and 100 slaves, from his wife. During his campaigns for the Senate and the presidency, he employed “abhorrent words towards people of color,”
(The Illinois Central was not just profitable for Chicago, it was profitable for Douglas, too: shortly after moving to the city, he began buying up lakefront property, sixteen acres of which he sold to the new railroad for $21,320.)
The Kansas-Nebraska Act, which Douglas authored and sponsored, is remembered as a scheme for opening the territories to slavery. In fact, it was Douglas’s scheme for overcoming Southern opposition to a railroad that would follow a Northern route to the Pacific—a route that would, of course, embark from Chicago, and run through Nebraska Territory, which had been designated as free soil by the Missouri Compromise of 1820.