"Most historians believe now that..."
Where have you been? They've known that since 1961! Kennedy and Goldwater got a lot of sympathy from people after that, and many think it helped the Republicans win seats in the senate (almost as much sympathy for the GOP since Nixon took over after Eisenhower died in 1955). Unfortunately, that didn't translate into better diplomatic relations, and WWIII still broke out between the Pan-Arab Federation, People's Union of India, the USA, ORU (Orthodox Russian Union) and the Oceanic Kingdom of Great Britain (Ireland, Australia, England, and Canada at the time) by 1962... Thank god Kennedy didn't die, or that war could have gone nuclear.