Bingham's political activity continued despite the Whig Party's decline. Campaigning as candidate of the Opposition Party, he was elected to the Thirty-fourth Congress, representing the 21st Congressional District. In Washington, DC, he roomed at the same boarding house as fellow Ohio Representative Joshua Giddings, a prominent abolitionist Bingham admired. Voters re-elected Bingham to the Thirty-fifth, Thirty-sixth and Thirty-seventh Congresses as a Republican. However, the district was one of two Ohio districts eliminated in the redistricting following the census of 1860. Bingham thus ran for re-elected from what became the 16th District. Known for his abolitionist views, he lost to Democratic peace candidate Joseph W. White, and thus failed to return for the Thirty-eighth Congress, in part because Union soldiers (mostly-Republican leaning), who were away from home fighting in the war, were not allowed to vote by mail in Ohio at the time. Nonetheless, the House of Representatives appointed him as one of the managers of impeachment proceedings against West H. Humphreys.