In looking at history, I would say he was about par for the course, given even today's standards. He didn't keep his word, (just ask those guys left on the beach at the Bay of Pigs), and he was a pain in the ass to the Secret Service whom were continually asked (demanded that) to cover his continual indiscretions with women, sneaking in and out of the White House.
Of course this week, we learn through the "Freedom of Information Act" that our beloved "Queen of Camelot" (Jackie) was no better, as her own memoirs tell of her affair with William Holden IN THE WHITE HOUSE, while good ole JFK was president.
Of course both he and his brother Robert were playin hide and go seek with Marilyn Monroe, so what I think his legacy is, is: A bunch of heathen children from a bootleggers family, were doin what heathen children do, in the Capital of America. And as usual, the American people are oblivious of it, and some worship them as royalty, when in fact, they were immoral degenerates with a good education, and few morals, that were exceptionally good, at not using the same door to sneak their playmates in and out of the White House.
One can defend them by saying: It was their private life, and none of our business, when in fact, they were continually making BAD DECISIONS in their own life, so why would they be better at making decisions affecting MY life.
It is like hiring a chauffeur that is a drunk, to drive you around.