In 1954, Bass was elected as a Democratic U.S. Congressman from Tennessee's 6th District, which included Pulaski. He was reelected four times. Having declined to sign the 1956 anti-desegregation Southern Manifesto, Bass was the only Democratic Representative from the rural South to vote for the Civil Rights Act of 1964. The only other Southern Representatives to vote for the bill were from large cities—Richard Fulton from Nashville, Tennessee, Charles Weltner from Atlanta, Georgia, Claude Pepper from Miami, Florida and four Representatives from Texas. Bass also voted in favor of the 24th Amendment to the U.S. Constitution in 1962. In 1963, Senator Estes Kefauverdied in office. Governor Frank G. Clement made no secret that he wanted to run in the special election due in 1964 for the final two years of Kefauver's term. To that end, he appointed one of his cabinet members, Herbert S. Walters, to serve as a caretaker until the special election. However, Clement's plan backfired when Bass defeated him in the Democratic primary held in August. In November, Bass defeated the Republican nominee, Howard Baker by only 4.7 percentage points—the closest that a Republican had come to winning election to the Senate from Tennessee at the time. Since the election was for an unexpired term, and in the Senate seniority is a very important consideration when being considered for committee assignments, office assignments, and the like, Bass was sworn in as soon as the election results could be certified in order to give him a slight seniority advantage over other freshmen Senators elected in 1964. Bass became Tennessee's junior Senator and prepared to run for a full term in 1966. Bass voted in favor of the Voting Rights Act of 1965. However, this race proved problematic for Bass. Clement still desired the seat for himself, especially since he could not run for reelection as governor in 1966. He wanted to avoid being forced out of politics, as he had once before when faced with term limits the first time in 1958. Bass lost the August 1966 Democratic primary to Clement, even though he received 10% more votes than in the previous election. Clement went on to lose resoundingly to Baker in the general election.
Later political career
Bass subsequently made two attempts to re-enter politics. He ran for the 1974 Democratic nomination for governor, but finished fifth in a nine-candidate field—well behind the eventual winner, Ray Blanton. In 1976 he entered the Democratic primary for his former House seat and won the nomination. The district, however, had been significantly redrawn since his previous service. Bass found himself running in a large amount of territory that he did not know and that did not know him. Much of this area was located in suburban territory near Memphis and Nashville that had turned heavily Republican, at least at the national level. Bass lost badly — by almost 29 points — to Republican Robin Beard.
Personal life
His first marriage to Avanell K Bass ended in divorce in 1967. He married Judy Bobo, of Nashville, in 1975; they divorced in 1979. He later married Jacqui Colter in 1992. After his 1976 loss, he moved to Florida, where he lived in Miami Shores until his death of lung cancer in 1993, aged 74, survived by his third wife. His first cousin is actor, Dewey Martin.