When John McCain ran for president in 2008, some commentary focused on the age gulf between him and Barack Obama. So McCain's announcement Tuesday that he will seek a sixth term in the Senate in November suggests that he must be near the upper end of the age range of Senate. Which he is. But, if McCain, who is now 78, is reelected, he probably won't even be one of the three oldest senators in the 115th Congress, much less history. McCain is so young by Senate standards that former senator Strom Thurmond (R-S.C.) won election three times when he was older than the Arizona Republican will be. Two other senators won election twice at ages older than McCain will be in January 2017.