Senator (1814–1868) best known for sponsoring the Wilmot Proviso, which aimed to ban slavery in land gained from Mexico in the Mexican-American War. Very rare ALS, one page, 6 x 4.75, April 4, 1857. Brief letter responding to a collector. In full: “I cheerfully comply with your request for my autograph.” Edge toning from adhesive remnants to reverse, otherwise fine condition. RR Auction COA.