that's my answer to the age-old question, "do the ends justify the means?" - which I consider to be a kind of paradox. You can't take two parallel Earths and have history play out with Course of Action A on one and Course of Action B on the other. Thus the question of whether the ends justify the means is always unanswerable.
However, it's a sure bet that the means you employ will influence how the ends turn out. With the August 6th anniversary of the bombing of Hiroshima just past (and Nagasaki yesterday, August 9th), it's certainly relevant to suggest that the entire Cold War was the direct outgrowth of the fact that we as a nation set the standard, by saying that yes these weapons can be used. I confess to almost total apathy about whether the bombs should have been used or not - after all, who's to say that the next Hitler wasn't vaporized on August 6th (certainly a nuke dropped on Berlin back in 1918 might have prevented Adolph's rise).
Still, there's always going to be debate, and it's impossible to separate it from pre-conceived notions and political opinion. For example, Tacitus enthusiastically links to yet another book and asserts that it's the "latest and best scholarship" backing the the bomb. Ampersand has a few countering links and suggests that it was a technical wording of the surrender terms that won the day (leveraging the fact that the Emperor was God). Interesting angle, notably absent from the reviews of Tac's book recommendation, only someone who's read it would know whether Amp's points are mentioned and/or refuted.
But regardless of whether we should have, we did. And that gave rise to the Cold War. Which gave rise to realpolitik and the support of proxy nations (like Afghanistan, where we funded a bunch of insane warlords whose subsequent misrule led to the Taliban coup). And that indirectly created the conditions for radical Islam to find great new recruitment talking points.
Who's to say that invading the Japanese mainland wouldn't have been worse? we don't have an alternate Earth to find out. Ultimately Hiroshima and Nagasaki serve history best by reminding us that we get what we pay for. The means dictate the ends.
Next year I hope I am able to attend the annual ISMRM conference in the beautiful city of Kyoto - which narrowly avoided the fate of Nagasaki. Aug. 6th will certainly be on my mind.