[megous]

This certainly is an interesting alternate reality exercise. If US didn't participate, would it become a military superpower? Would Korea/Vietnam/middle east wars/... happen? What would USSR do? Would there be a nuclear race? Would Nazis be able to control most of Europe, long term? Or would they self-destruct with their megalomaniacal desire to expand their reich?

I guess I'm glad US did participate, because I wouldn't be sitting here otherwise. :) Hard to argue against something that resulted in me existing.

Anyway, whether something is justifiable is subjective. Millions of people who died from US actions during WWII and millions who were killed by US after the WWII may have had a different opinion. To the dead, who the executioner was doesn't really matter after all.

It's also probably good to compare what happened, instead of what might have happened, because that is unknowable.

Nazis killed millions and had a disgusting ideology. US killed millions too, and one has to wonder what their ideology was or how important it was if they decided to kill hunderds of thousands of civilians just to show their new found military power, without even thinking about the victims (at least some National Geographic documentary I've seen recently mentioned that there were no indications in archives/diaries that anyone involved in decision making mentioned civilian lives that would be destroyed, while dropping the atomic bombs). How about millions of destroyed lives in the fight to "stop the reds"?