An average of seven senators have retired from the chamber each cycle during the past quarter-century; no incumbent up for reelection next year has yet closed the door on a 2018 bid.
Since 1972, all seven sitting U.S. Senators who ran for reelection in the cycle of their failed presidential bid won another term – each by double digits.
The five U.S. Senators who have announced their retirement during the 113th Congress are 10 years older on average than any 'retiring class' from the chamber over the last five decades.
At least one first-term incumbent has been defeated in 48 of the 52 election cycles during the direct election era.
Three fell in 2014 and more than half of all defeated U.S. Senators over the last 100 years have been in their first term; at least one first-term incumbent has lost reelection in 47 of the 51 election cycles during the direct elect...