The cracks in the Second Party system that were revealed in Massachusetts in 1850 became chasms four years later. The Kansas-Nebraska Act essentially destroyed the Whig Party in the South. In the North, however, it was a different story. Both major parties fell into a mess in various states, reacting to angry Northern antislavery voters determined to send a message to the South and antislavery Congressman to Washington. The chosen messenger was a lot less clear. In New England, anger at the South, anger at the Democrats in the Pierce Administration, and anger at the Irish-Americans who voted for the Democrats combined to lead to a Know-Nothing sweep of the region. In the Mid-Atlantic, the Whigs declared themselves the antislavery party, and voters listened. In the upper Midwest, Free Soilers and Whigs combined to form the Republican Party, which also did well.
Yet there was no place for antislavery Democrats in any of these formations as of yet, until the Illinois legislature elected its U.S. Senator. There were three candidates: Incumbent Democrat James Shields, Whig Abraham Lincoln, and antislavery Democrat Lyman Trumbull. Lincoln had the most support in the legislature, but not a majority. As such, the legislature repeatedly deadlocked…until Governor Joel Mattieson’s name was put forward as a compromise choice for all Democrats.
This was when Lincoln made his move: he ordered his Whig supporters to back Trumbull, who promptly won and sent shockwaves through the state and the nation. Among other things, it damaged the standing of the leading politician in the state – Democrat Stephen Douglas. That could very well have impacted his presidential candidacy two years later.
More importantly, it gave Democrats a place in the Northern antislavery coalition, and pushed Northern leaders and voters towards the Republican party as their vehicle, rather than the Whigs or the Whig-like Know-Nothings. Had Lincoln been elected as a Whig (or been defeated by Madison as such), it would have extended the Whig-Democrat divide on slavery all the way to the Mississippi River. Instead, it was halted somewhere between Chicago and Pittsburgh, before receding in 1855 when the New York Whigs merged with the various antislavery factions outside of it to form the Republicans.
Illinois’ 1854-5 Senate election marked the true hammer blow for the Second Party system. With Whigs and Democrats working together against slavery in a major northern state, the model for the antislavery alliance was set.
