There were two primary political parties in the United States during the 1840’s, the Whigs and the Democrats, neither of which supported the abolition of slavery. At this time, the state of Texas had been admitted into the Union as a slave state, and when war against Mexico was declared in 1846, northern Whigs were concerned that lands gained from the conflict would eventually be turned into more slave territory. The debate regarding this issue solidified the divide between North and South and fractured the political parties. In 1848 a new political party was formed, called the Free Soil Party. This party's platform included a commitment to banning the admission of any new slave states.
The Southern states strongly opposed any federal imposition of slave restrictions, claiming that such decisions should be left to the states. Northern Democrats were aware of the concerns of their constituents and believed they would lose congressional seats unless a restriction was in place. To accomplish this, Representative David Wilmot from Pennsylvania proposed an amendment to a war appropriations bill, known as the Wilmot Proviso, which would have banned slavery in any new state formed from land acquired from Mexico. The amendment never won Senate approval, but the debate sharpened the conflict between North and South. The slave state issue was extremely divisive, and as a result was ignored by both parties in the next election.
One faction of the New York Democrat party, known as the Barnburners, withdrew from the party in protest. These eventually joined the Liberty Party and abolitionist Whigs in forming a new political group known as the Free Soil Party. The party did not support abolition of slavery in existing states, and even nominated the former President Van Buren, who owned slaves, as their presidential candidate for the 1848 election. The Free Soil Party platform did include a ban on the admission of any new slave state to the Union.
The Free Soil Party took their name from their slogan, “Free soil, free speech, free labor, free men.” One of their primary concerns was the inability of states which did not employ forced labor to compete with a state which did not have to pay its workers. The party only carried a small percentage of the presidential votes, but they pulled enough votes away from the Democratic candidate to ensure that Zachery Taylor, the Whig candidate, won the election. In addition, they took 16 congressional seats.
Free Soil Party candidates did much better in state and local elections in the Midwest, especially in Ohio and Wisconsin. In Ohio, their candidates worked with the Whig state congressmen and successfully abolished most of the "Black Laws," discriminatory restrictions on black individuals. The Compromise of 1850, a series of legislative pieces which included the Fugitive Slave Act and the admission of California as a free state, weakened the national influence of the party.
In 1852 the Free Soil Party again ran a candidate for President, John Hile. This time the party won about half the votes they had taken in the previous election. Due to this poor performance, the party disbanded, and by 1854 the Free Soil Party membership was absorbed into a new group, the Republican Party. The Republicans ran their first presidential candidate, Abraham Lincoln, in 1860 on a platform to end the expansion of slavery.