Parti du sol libre
Originally a Whig, Wilson was a founder of the Free Soil Party in 1848. He served as the party chairman before and during the 1852 presidential election. Wilson worked diligently to build an anti-slavery coalition, which came to include the Free Soil Party, anti-slavery Democrats, New York Barnburners, the Liberty Party, anti-slavery members of the Native American Party (Know Nothings), and anti-slavery Whigs (called Conscience Whigs). When the Free Soil party dissolved in the mid-1850s, Wilson joined the Republican Party, which he helped found, and which was organized largely in line with the anti-slavery coalition he had nurtured in the 1840s and 1850s.