Further on the counterfactual issue: we always advise doctoral students and indeed each other that historians should be able to give an elevator pitch for any new project, and that this pitch should always answer the “so what?” question—i.e., you’re writing about the history of the glass-bead game of the Pacific islanders in the 1940s; so what?
“So what?” is of course always a challenge requiring you to counterfactualize twice over: it demands you to say (a) “but for” this event or phenomenon, x important thing would not have occurred and also (b) at a meta or historiographical level, “but for” my research, we cannot understand y important thing.
Believe me, I always worry about these things myself. Writing as I am about Bretton Woods, I get people saying either “That’s great!” and beaming, as if at a slow-learning child who has managed to write his name, or else looking dumbfounded completely. Why Bretton Woods, you can see them thinking—when you can’t see them thinking, what’s Bretton Woods?
Usually the answer has to do with the purported goals of the system—freer trade and stronger, better distributed economic growth—both of which were realized in the quarter-century or so that the system actually operated. But the connection between Bretton Woods and those trends is not easy to pick out of the data.
I think it’s more important to say, Bretton Woods was the first major opportunity to get the US to sign on to an international system in the post-1945 world. To have failed at the first hurdle—to have permitted Robert Taft and his ilk to scuttle the initial effort—would have increased the perception that isolationism still dominated the American temper, or at least the US Congress, and would have shaken the foundations of the whole postwar international project. So it was important to adopt Bretton Woods simply to set a pattern of postwar international cooperation; otherwise (note counterfactual) the forces of isolation would have been emboldened and strengthened.
Which raises a question: why did the Roosevelt administration decide to do Bretton Woods first? It was complicated, and difficult to explain. Perhaps Keynes’s answer was right: that it was precisely the intrinsic dullness of Bretton Woods that made it an ideal initial effort. “This is such a boring subject that no public enthusiasm can be roused by discussing the details, whilst it would be frightfully dangerous to be open to the challenge of sabotaging the first international scheme. Anyone with isolationist origins will think twice before doing so.” But this turned out to be an incorrect prediction; there was considerable opposition to overcome.