I just saw a show on this the other night. Evidently, JFK and his older brother were opposed to the war, but joined because it was what their father wanted, and he got what he wanted always. (At least until his stroke.)
Anyway, after JFK was awarded a medal (not sure which one) his elder brother was so depressed that he went to his room and CRIED, and was determined to earn a more prestigious medal. He figured he had his chance when he was asked to make that flight in which his plane blew up.
JFK had no interest in politics but it was what daddy wanted so he did it.
Very interesting show. It was called 'The Kennedys: The curse of power'.. or something like that.