without JFK Nixon wins i think, and Humphrey is the nominee in 1964
i don't understand why people think that without JFK, Nixon would be favored in 1960. It was after all a recession year (a mild recession, yes, but the second in two years), the GOP had been in power for eight years (only in 1988 in the postwar era did a party manage to stay in power for over eight years), and the Democrats were clearly the majority party (as shown by their edge in Congress.) Yes, JFK won the Catholic vote heavily, and much of it had gone to Eisenhower. But Ike's popularity among Catholics (and others) was a personal, not party , matter, and could not be transfered mechanically to Nixon. The Baptist Harry Truman had done about as well among Catholics in 1948 as JFK did in 1960. My guess is that without a JFK candidacy, any Democratic presidential nominee other than the divorced and dovish Stevenson would have won the Catholic vote decisively.
Moroever, there certainly are reasons to think JFK's religion hurt him at least as much as it helped him: How else does one explain how not only in many southern states but in border states like OK JFK acutally did worse than Stevenson had done against the immensely popular Ike in the year of peace and prosperity 1956?
https://en.wikipedia.org/wiki/1960_United_States_presidential_election_in_Oklahoma https://en.wikipedia.org/wiki/1956_United_States_presidential_election_in_Oklahoma
This doesn't mean that the Demcorats were wrong to nominate JFK. Once he was a candidate and had won the WI and WV primaries, to reject him at the convention would look like it was done because of his religion and could lead to a Catholic backlash against the party. But if JFK were not a candidate, a Protestant nominee who was not terribly controversial--e.g., Symington--would IMO be favored to defeat Nixon.