I know the OP says " Assuming that butterflies don't prevent JFK's election to the Senate" but I rather think this will prevent JFK's election to the Senate. One reason Lodge was so vulnerable in MA in 1952 is that the Taftites hated him for his role in helping Ike defeat their hero for the 1952 presidential nomination. If like most incumbents Dewey is renominated without much opposition, the GOP will unite behind Lodge. And if Dewey is popular enough to be re-elected, Dewey will probably carry MA as well (MA was not much more Democratic than the nation as a whole in the 1952 presidential election in OTL: https://en.wikipedia.org/wiki/1952_United_States_presidential_election)
I hope not.
I hope we’d get an older, more seasoned JFK maybe in ‘64 or ‘68.
Would his health be up to a 1968 run? By that I don't mean he'd be confined to bed but I can see '68 JFK as having faced some significant health scares and it would have been increasingly difficult keeping those from the public.
Regarding the 1956 run I can see him doing pretty well in the primaries but ultimately passed over. He'd be courted as a VP though and if not would be young enough to try again in 1960 or 64, depending on who controls the White House.
I agree that his health issues make for an interesting story in their own right — chronic back pain, and Addison’s disease, and probably being over-medicated.Would his health be up to a 1968 run? . . .
That's possible, but I don't think it's certain. The conflict between moderates and conservatives predated 1952 - in fact Dewey and Taft had a blood feud that made them bitter enemies. I expect there'd be much conflict between President Dewey and Senator Taft, and Senator Lodge would support his fellow moderate Dewey on key issues over the opposition of the conservative Taft. In that case, Taftites would still hate Lodge, and many would prefer Kennedy to win in order to get rid of him.
I agree that his health issues make for an interesting story in their own right — chronic back pain, and Addison’s disease, and probably being over-medicated.
Taft was a party loyalist, though. He tried to get along with Ike after the latter was elected--for example, backing Charles Bohlen's appointment as Ambassador to the USSR against McCarthy's objections. I think he would try to maintain at least a facade of unity with Dewey in 1952 and hope his own hour would come in 1956. This would involve supporting Lodge for re-election in 1952.