He was later admitted to the bar at Wilkesbarre, Pennsylvania, in 1834. He soon began practice at Towanda, where he afterward resided. He was first brought into public notice from his support of Martin Van Buren in the presidential race of 1836. He helped to found the Republican Party and was a Republican Senator from 1861 to 1863, filling out the unexpired term of Simon Cameron. He then became a judge of the U. S.
Court of Claims in 1863. David Wilmot was an avid abolitionist. He became a part of the Free-Soil Party, which was made chiefly because of rising opposition to the extension of slavery into any of the territories newly acquired from Mexico. Not only was he opposed to the extension of slavery into “Texas,” he created the Wilmot Proviso. The Wilmot Proviso, which is obviously named after its creator, was an amendment to a bill put before the U. S.
House of Representatives during the Mexican War; it provided an appropriation of $2 million to enable President Polk to negotiate a territorial settlement with Mexico. David Wilmot created this in response to the bill stipulating that none of the territory acquired in the Mexican War should be open to slavery. The amended bill was passed in the House, but the Senate adjourned without voting on it. In the next session of Congress (1847), a new bill providing for a $3-million appropriation was introduced, and Wilmot again proposed an antislavery amendment to it. The amended bill passed the House, but the Senate drew up its own bill, which excluded the proviso. The Wilmot Proviso created great bitterness between North and South and helped take shape the conflict over the extension of slavery.
In the election of 1848, the terms of the Wilmot Proviso, a definite challenge to proslavery groups, were ignored by the Whig and Democratic parties but were adopted by the Free-Soil party. Later, the Republican Party also favored excluding slavery from new territories. Because of this information on David Wilmot, it is obvious to say that he was against the decision of the Dred Scott Case, which was that Congress had no power to prohibit slavery in the territories. David was a passionate abolitionist. He played an important role in the separation of the north and south with the issue of the Mexican territories, especially with the Wilmot Proviso. He was also an influential creator of the Free-Soil Party.