At this time, Lincoln was not an abolitionist per se, but he was firmly committed to the containment of slavery within the United States. Though he was morally opposed to slavery, he had no wish to upset the balance of the union by campaigning too harshly against the rights of the southern states. His approach had always been to campaign for state-sponsored repeal rather than the force of federal legislation. There can be no disputing that Lincoln accepted the existence and continuation of slavery in the southern states during much of the 1850s. However, with the introduction of Douglas's popular sovereignty, Lincoln aired his fears that the African slave trade would presently be revived, turning America into vast slave empire.
In an effort to prevent this scenario from occurring, Lincoln decided to re- enter politics, with the clearly defined goal of assailing Douglas's Kansas-Nebraska Act. Originally he had no intention of campaigning directly, but after a powerful speech at Peoria, he was elected once again to the Illinois General Assembly, and found himself as a potential candidate for a Senate seat.
After gaining the support of the Whigs, Lincoln resigned his newly won seat in the state legislature and made a concerted push for Senate election. Although the balloting was close, Lincoln again came up short at the hands of his Democrat opposition, and found himself sidelined once again. This was a keen disappointment for Lincoln, and once again he retreated into the confines of his legal practice, his political future uncertain at best.
Despite Lincoln's loss, the national tide against Douglas was beginning to rise. Douglas's Kansas-Nebraska Act was fiercely opposed in the Senate by politicians of national reputation such as Salmon Chase of Ohio, William Seward of New York and Charles Sumner of Massachusetts. After Sumner aired a series of sharp criticisms against several supporters of popular sovereignty, he was attacked on the Senate floor by Preston Brooks of South Carolina. The nation was beginning to come apart at the seams.
Nowhere was the tension over popular sovereignty more palpable than in Kansas, where Douglas's legislation was being put to the test. With the gauntlet laid down for a shouting match, free-soilers and slavers alike rushed in to settle Kansas in hopes of controlling state policy. Rival delegations quickly emerged, with a pro-slavery government assembling in Lecompton and a rival free- soil government assembling in Topeka. Then, in May of 1856, a group of slavers sacked the free-soil stronghold of Lawrence. Throughout the summer and into the fall, open civil war raged in Kansas between the rival factions. In one of the most significant incidents, a virulent abolitionist named John Brown hacked five slavers to death at Pottawatomie Creek. Popular sovereignty was quickly degenerating into anarchy.
Out of the increasingly heated debate over the slavery question, a new political party emerged in time for the 1856 presidential elections. Called the Republicans, they were an amalgamation of various factions united by their opposition to the spread of slavery. For president, they nominated the western explorer John C. Fremont on a platform of expansionism and opposition to popular sovereignty. At the convention, Lincoln himself received a significant portion of votes for vice president, but slipped off the list on succeeding ballots due to his regional obscurity.