I would never trust a Kennedy with my security.
Scoop Jackson, yes. But even the sainted Truman and JFK had grievous flaws and blind spots when it came to our national security (though they tried to correct some of their worst mistakes). Truman was grossly naive and gullible about the Soviets in 1945-47, and only started to take the peril seriously when Stalin made it overwhelmingly clear that his appetite for subjugating other nations was voracious. Our military was gutted in the late '40s - while the Congress of the time bears a lot of responsibility as well, it is certain that Truman did little to hold the line for a stronger defense. Then Truman and pals totally failed to recognize the extent of the treats in East Asia - it can be easily argued that Truman/Acheson blunders and softness led directly to the Korean War.
As for JFK, he also had his good moments, but he was often more talk than intelligent action. He was directly responsible for the blunders that led both to the Bay of Pigs fiasco and also the unnecessary "Cuban Missile Crisis".... let it also be said that JFK did nothing to address Vietnam effectively, though it can certainly be debated whether there was anything that would work short of bombing North Vietnam into oblivion (which of course would have opened its own set of risks with the PRC and USSR).
Anyway, I'm not sure that even JFK or Truman stands as any paragon of strong, intelligent defence, though they are both soooo much better than what's followed.