Passage of the Kansas-Nebraska Act and its effective repeal of the Missouri Compromise reawakened Lincoln’s passion for politics, and he threw himself into the congressional election campaign in the fall of 1854, crisscrossing Illinois to deliver speeches against the Kansas-Nebraska Act and in support of anti-Nebraska candidates. He even allowed himself to become a candidate for the Illinois General Assembly (albeit reluctantly at first). As the election campaign reached its climax, Lincoln’s name began to circulate as a possible nominee for one of the state’s U.S. Senate seats. In November and December 1854, he wrote confidential letters to political allies, seeking support for his candidacy and information about his prospects. He won a seat in the Illinois House of Representatives, but in late-November 1854, he declined to serve in order to run for the U.S. Senate. When the General Assembly met in a joint session on February 8, 1855, to elect a U.S. senator, Lincoln and Shields received the most votes in the first round of balloting, with forty-five and forty-one votes respectively. As neither received a majority of votes, several more rounds of balloting ensued. Lincoln received a majority of the anti-Nebraska votes until the tenth and final ballot, when he withdrew and urged his supporters to vote for anti-Nebraska Democrat Trumbull in order to ensure that an anti-Nebraska politician filled the seat. With the votes of Lincoln’s supporters, Trumbull won the seat. See 1854 Federal Election.

Yates had recently been defeated by Democrat Thomas L. Harris in his bid for reelection to Congress in Illinois’ Sixth Congressional District, garnering 49.5 percent of the vote to Harris’ 50.5 percent. Yates, a Whig, had opposed the Kansas-Nebraska Act, while Harris spoke in favor of it. On the campaign trail, Harris touted “the glorious principle of popular sovereignty” promoted by the act, and like Douglas, argued that the measure would extend freedom in the territories.

The Democratic Illinois State Register similarly argued during the 1854 election season that popular sovereignty would ensure that Kansas and Nebraska entered as free states, due to factors such as the self-interest of territorial settlers and the unsuitability of conditions in the territories for large-scale slave labor.