That sounds like something Judt would have said. I specifically recall David Fromkin saying that WWII should really be called The Great War, Part II, so it's certainly got credence in history circles (of course, ironically, the US and Japan are one of the major switches in terms of allies/adversaries from WWI to WWII).

To the point about whether we should nuke Japan to annihilation or invade, Ellsberg makes the point that it's a false choice, that Japan was going to surrender when they did without use of the bomb (and FWIW, 7/8 5-star generals or admirals in WWI, including Eisenhower, thought that it was unnecessary). The argument against the bomb basically rests on the premise that (1) we were already targeting civilians in Japan from March 1945 onward (the time-delayed bombs, for example, were supposed to hit the responders). Curtis LeMay was brought over from the bombing campaign in Europe specifically because he was so damn good at it. The firebombing of Tokyo in spring 1945 killed at least 20,000 more people than the A-bomb on Hiroshima did, and the list of other cities in which 10,000-50,000 civilians were killed is long. None of that required an A-bomb.

There may be some reason to think that an A-bomb was more terrifying and thus hastened the surrender, but there are reasons to think otherwise, as well. Mainly, the Japanese-Soviet non-aggression pact was expired, and the Japanese surrendered just as Soviet troops were amassing in and around Mongolia. Japan was stretched thin enough that there was no way to survive opening another front, thus they gave up. Of course it's an unknowable counterfactual but there's at least reason enough to consider that the atomic bomb was a bit player and not a star of the Pacific theater.

However, it sure as fuck was a star of the war generally, given that everyone knew it was coming, but no one knew when or what might happen when/if deployed (and that everyone knew the H-bomb was also inevitable as early as 1942). Ellsberg argues that the use of the bomb was of course meant as a punitive measure against Japan, but given that the widespread destruction of civilian centers was trivial by August 1945 (as the B-29s were having an easy enough time avoiding being shot down by then), the real target was Berlin. As in, "Dear Stalin, This is what we have in store for you if you violate the Allies' claims in Berlin and the rest of Germany." It's sort of a cynical view of things, but it's difficult to not read the arms race cynically (since they were plotting the destruction of humanity).

Edit: We apparently tried the same strategy in Germany, but due to local conditions (which include building material and weather patterns) we were only able to create firestorms twice--Dresden and Hamburg (and of course we were originally developing the bomb for Hitler). The strategy was in play from 1942 on, however, so it's wrong for anyone to think that Japan was unique in the targeting of civilians as a war strategy.