If not for the atomic bomb, would the US have defeated Japan?

I've gone in and done an edit, as I went back and read your [i]whole[/i] monologue (my fault) on this question. In reading this at first, I'd replied about the question regarding Japan and had stopped there. To that, my answer is still "yes," we would have defeated them, but at a much higher human American and Allied cost.

Then, I read what I initially wrote, and did what I should have done at the onset......that being to have read your whole thread. That was totally my mistake, so apologizies on that end. BUT, on to the rest of a reply.......

Having read your premise, I have to shake my head. You never mentioned the politics of it all, the boundaries set that we often go to war under, and America's war fighting capabilities, that are so often, knee-capped by said politics and politicians.

You didn't mention whether or not you were a veteran, I didn't see that. If you are or had been then I think you'd have come with a different perspective. I am one....twice over, and I'm very confident with our ability unlike yourself.
As well, you never mentioned symmetrical vs. assymetrical warfare, their differences and response applications, and that in finality, we are still a nation of laws, in which we [i]do[/i] abide by the Geneva Convention. To understand that last sentence, you need only look at Russia and it's invasion of Ukraine, and it's barbaric, indiscriminate shelling of civilian population centers to sow fear, before unleashing the Wagner Group who go in and mop up, raping and summarily executing said civilians before dumping them in mass graves. Russia IS everything we are not.

That, my friend, is a salient difference in our warfare. And, to be clear, we have made our own mistakes, but we have generally fought our conflicts with one hand behind our back, based either on the fact as I stated above, that we are a nation of laws, or that, we get that other hand inexorably tied behind us by our politicians, who have no business mudding the water once we have unleashed our dogs of war.

War fighting is a trust. The trust that our military leaders will endeavor forever to do the right thing. It is why we have Annapolis and West Point. It is where we inculcate these boots with a battery of subject matter that puts them in the best place to take charge and command the battlefield when they graduate. They are motivated, and they......are.....magnificent.

In conclusion, I don't share your hand ringing. Neither do millions of other Vets of our joint military services because we lived it and understand it's capabilities, and the frequent hamstringing of our combined arms by clueless politicians.🤬

At any road, you did ask.....