More than two terms.

[Captain Chaos]

Would JFK actually run against an incumbent President seeking a 3rd term? If not, I think Eisenhower would defeat any Democrat who ran in 1960.

Eisenhower then retires in 1964. Kennedy throws his hat into the ring, wins the Democratic nod, and selects Senator Fulbright as his running mate.

Vice President Nixon wins the GOP nod and picks either Barry Goldwater (if he needs to cement support from the conservative wing) or William Scranton (more acceptable alternative than the divorced and re-married Nelson Rockefeller). Henry Cabot Lodge would probably be Secretary of State in an Eisenhower 3rd term and not interested in seeking the Presidency.

Kennedy would capitalize on voter fatigue with 4 more years of a Republican presidency and run on a slogan of getting America moving again. Fulbright ensures Democrats hold most of the South (Kennedy overlooks his opposition to civil rights).