Miller was elected to the
Iowa House of Representatives in 1955, and to the
Iowa Senate in 1957. Miller was first elected to the
United States Senate in 1960. In a race to replace the retiring Republican Senator
Thomas E. Martin, Miller defeated Iowa's sitting governor,
Herschel C. Loveless, in a
close contest. Miller was a member of the Senate Finance Committee. He was reelected in
1966, easily defeating Democrat
E. B. Smith, but in
1972 was defeated in an upset by Democrat
Dick Clark. During a phone call in the early hours of the morning following that election,
President Nixon told
Henry Kissinger that "we lost Jack Miller because he's a jackass." Miller voted in favor of the
Civil Rights Act of 1964, as well as the
24th Amendment to the U.S. Constitution, the
Voting Rights Act of 1965, and the confirmation of
Thurgood Marshall to the
U.S. Supreme Court, while Miller did not vote on the
Civil Rights Act of 1968. ==Federal judicial service==