Henry Wilson was the 18th vice president of the United States from 1873 until his death in 1875 and a senator from Massachusetts from 1855 to 1873. Before and during the American Civil War, he was a leading Republican, and a strong opponent of slavery. Wilson devoted his energies to the destruction of the "Slave Power" – the faction of slave owners and their political allies which anti-slavery Americans saw as dominating the country.
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, and anti-slavery 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.