@Jimcat: This doesn't necessarily diminish the value of the rest of your position, but fission was discovered only in 1938 (albeit by [Jewish in at least one case] Germans). It was only hypothesized as possible in 1934.
Nevertheless, fission was an extremely new fact, and the fact that enormous (possibly historically incomparable) resources were necessary to proceed to building a weapon in the time available based on that technology probably made it likely than only a few nations had the resources to contemplate the effort, never mind bring it to fruition in the midst of a war.
FWIW, if the rest of the political developments post-war had proceeded apace without the US having developed and used a nuclear weapon in WWII, I feel confident we would have had a nuclear war circa the Cuban Missile Crisis. Why? Curtis LeMay wouldn't have seemed so insane— no one would have known just how bad it would be, and some one would have pushed the button, which would likely have meant everyone pushing all their buttons.
All of which is to say: @Misterben: I think you're mistaken regarding deterrence. It is exactly because deterrence works through mutually assured destruction that you are correct to say that, "[i]t's like we're the world's biggest suicide bomber." Only "we" is anyone who starts a nuclear war with another nuclear power, and we aren't "like" the world's biggest suicide bomber— we are the worlds biggest suicide bomber.
The real question you have to ask yourself is, "would I submit to nuclear blackmail if I couldn't respond in kind?" If the answer is yes, then you may find yourself never understanding those of us who prefer the tension of possible conflagration to the reality of submission.
I'm not suggesting this is a perfect result. It isn't. It's just the least bad result given the cards in play. Someday, probably after my atoms have dispersed permanently, maybe we'll find a way to resolve this problem. Maybe it'll be through that dreaded one-world government (Oooh! Scary!). Maybe not.
Which brings me back to Ed's actual point: the Rs are just sure that if they look like their shitting their pants thoroughly enough, people will be scared of a change that will, 1) cost their political contributors a few bucks, 2) have no other meaningful result. Because, honestly, all this really says is we won't obliterate Venezuela, or Cuba, Somalia, or some other country full of brown-skinned folks no matter how much fun their juvenile troglodyte supporters might think it'd be when they get uppity. Iran and North Korea? Well, you just never know, now do you?