The preventive motive behind Pearl Harbor (War and Peace in East Asia, Lecture 9)

Sometimes lectures write themselves. Unsurprisingly, I like it when that happens.

Today, we focused on Japan’s decision to expand its regional war, focused on pacifying China through the late 1930s, into a global war by attacking not only Pearl Harbor on 7 December 1941 but, in the same timeframe, Thailand, Malaya, The Philippines, Wake Island, Guam, Hong Kong, and the International Settlement at Shanghai. Knowing that the first target would likely draw the United States into the war—though hoping to cause a significant delay—why would Japan turn some of its focus away from its main theater in China?

This won’t come as much of a surprise to IR folks, but Paine’s account of the decision framed it quite well as an escalation of the war driven by a commitment problem—specifically, the fact that the United States, which has been mobilizing for a while and had embarked on building a two-ocean navy, would soon outstrip Japan in naval power; Japan’s leaders calculated roughly even odds of defeating the United States by late 1941, given their respective shipbuilding programs and future potential, followed by a sharp decline—which would allow the US to prevent the fall of China, which Japan had long viewed as critical to its survival as a great power.

In fact, the United States made a series of peace proposals before December’s attack, most of which involved withdrawals from China—but which, ex post, were clearly preferable to the outcome of the war. Why didn’t Japan cut such a deal? Paine is worth quoting here:

[P]eace on American terms, entailing a withdrawal from China, would lead to the gradual impoverishment of Japan and would undo the efforts of generations of Japanese to transform their country into a modern power. War with the United States, on the other hand, offered a 50-50 chance of success (p. 185)

In other words, cutting a deal would allow US power in the region to grow unchecked, and such increased power could be used, down the road, to force Japan out of China anyway. If the worst outcome of a war would be similar, then rolling the dice before military prospects got worse—as Japan’s leadership expected—might’ve looked pretty attractive.

Interestingly, we’ve also got a story about the timing of war in the shadow of shifting power, but rather than the typical rising-declining state story, we’ve got one where in the late 1930s Japan expects to improve in the short term—so it waits before attempting a knockout blow—but to decline in the long term. So while some work finds that there’s no particular time during a shift in power that’s more war-prone than others, I wonder if taking a step back temporally, considering a short-term versus long-term changes in power, might alter those expectations…