The so-called Greatest Generation ruined war for everyone who came afterward. By trying to get it over with, the combatants in World War II developed such super-weapons that no rational person could advocate for war once these doomsday bombs existed.
The eager fans of warfare nowadays who idealize the Second World War and want to see grand mobilizations of force like that should be allowed to have their own great war, but they can't. The time line that spanned the climax of conventional war and entered the Nuclear Age has already run. Those glorious fireballs at Hiroshima and Nagasaki were the last and greatest expression of unlimited warfare. They set a standard we cannot afford to maintain, let alone surpass. The days of the grand existential struggle ended. The days of limited war began. Over all hangs the specter of nuclear murder-suicide.
So what's left for the fantasizing adolescent who wants to be a hero with a gun? Your life will be expended in a Police Action, or a surgical strike, or a hobbled, endless march through irreparably damaged failed states. How deeply satisfying.
If the architects of the Second World War had known better, or if we'd been lucky enough to fail at unlocking the deadly potential of the atom, we could have had that bloody and devastating invasion of Japan. If, at the end of it all, we still only had propeller aircraft, oil-fired warships, large but conventional explosives and brave men willing to take these weapons into battle, we could simply take a few years off to mop up the blood, bury the dead, shore up the walls and raise a few more kids before getting back down to the serious clash of cultures that should end with one -- and only one -- victorious.
Without nuclear weapons we could have had World War III with the Soviets. We could have killed Vladimir Putin's parents, so we would have a different person to deal with now. But of course "now" would be totally different. Maybe our forces would have faced the same fate as Hitler's and Napoleon's, leading us to withdraw, if not capitulate. Or we might have teamed up with the Russians to overrun China in a sort of reverse-Mongol-horde scenario.
Alas, we came out of the war under the shadow cast by the upward billow of atomic incandescence. Weary veterans came home eager for peace and a future without massive conflicts and huge slaughter. Those guys didn't know how good they had it, did they? Imagine that: a unified world settling disputes by courteous and rational exchanges of ideas. Crazy.
It obviously didn't work, but you have to give them credit for floating the notion. The warriors of our greatest conflict thought they were settling something for good. They used every tool at their disposal to put that thing to bed. War: been there, done that, done with it.
We insult the memory of people who fought to defeat tyranny and end the need for the wars tyranny breeds when we either practice tyranny or pine nostalgically for a past or future in which we are finally free to bump each other off as we see fit. I offer that for whatever it is worth to a species tearing at itself as it fouls its planet.