Henry Wilson was the 18th vice president of the United States, serving 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 "Slave Power", the faction of slave owners and their political allies which anti-slavery Americans saw as dominating the country.