Carpenter ran unsuccessfully for mayor of Scottsbluff, Nebraska in 1931, but the next year was elected to the Seventy-third Congress (March 4, 1933 – January 3, 1935) as a Democrat for the 5th District. He did not run for reelection, since he was running for Governor of Nebraska in 1934. Failing to get the Democratic nomination, he next ran for a seat in the U.S. Senate but lost the election, coming in a distant third place with 18% of the vote, as he was running against the incumbent independent Republican George W. Norris and another Republican candidate. Norris won the election.