Iowa went through a stretch in the 1970's as the revolving door of the U.S. Senate. With a combination of defeats (Miller, Clark, Culver, Jepsen) and retirements (Hickenlooper, Hughes), no Iowa senator was re-elected from 1966 to 1986.
Nowadays, Iowa is a giant of Senate seniority with two five-term senators, outranked in total now goes to North Carolina. Since 1968, no one except Jesse Helms has been re-elected to the U.S. Senate from the Tarheel State.
Granted, Helms held that seat for 30 years. Elizabeth Dole took his place in 2002, only to lose her re-election bid to Kay Hagan this year. But it's the other Senate seat that has really seen turnover.
The last senator re-elected to the Class 3 seat was Watergate era hero Sam Ervin in 1968. Since his retirement in 1974, the seat has seen no fewer than seven senators, in a sequence that reads like a list of Spinal Tap drummers.
Believe it or not, this isn't even the highest turnover era in North Carolina history. Through a combination of deaths, appointments, and primary defeats, six men held the Class 2 seat in 12 years between 1946 and 1958. That included the infamous 1950 primary, when Willis Smith beat appointee Frank Graham. Jesse Helms, who later held this seat, made his bones working on the race-baiting Smith campaign, which featured a faked photo of Graham's wife with--a black man.
My, but things have changed.