The Free-Soil party was organized in 1848 to oppose the extension of slavery into the territories newly acquired by the United States from Mexico. Among its leaders was Salmon P. Chase. The Free-Soil forces, composed of former Liberty party members, antislavery Whigs, and certain New York Democrats known as Barnburners, chose former president Martin Van Buren as their presidential candidate in 1848. Although they failed to carry a single state, the substantial Free-Soil vote in New York helped the Whigs defeat the Democrats in that state and thereby win the presidency for Zachary Taylor. They did, however, elect a number of congressmen. The party weakened in the 1852 election; most of its members later joined the new Republican party.