[Working backward from the year 2000 toward America’s beginnings.]
That war started in 1931 when Japan, which had industrialized and somewhat Westernized itself in the years since 1854, moved its armies from Korea (which it had occupied since winning the Russo-Japanese war of 1905) into Manchuria, which was nominally under Chinese sovereignty. Japan was in possession not only of Korea, but of the Shantung peninsula, a part of China formerly German-occupied, and awarded to Japan by the Versailles peace treaty of 1919. By the 1920s. Japan was observing chaos in neighbor country, and took advantage of what seemed a historic opportunity.
China had overthrown its emperor in 1911 and reconstituted itself as a republic, but within a few years had become divided among various contending regional war lords. In effect, China was undergoing a slow-motion civil war. By the mid 1920s, Chiang Kai-shek and his Kuo Min-tang party had emerged triumphant among the warlords, but a small but growing communist faction that had been born in Shanghai had survived Chiang’s attempts to destroy it, and had (by means of the famous Long March of several thousand miles) established itself in its own territory in northwestern China. In the face of Japanese aggression, Chiang’s response was divided and reluctant. (The Japanese invasion, he said, was like a cancer of the skin, whereas the Communists were cancer of the vital organs.)
Japan had managed to defeat the Czar’s armed forces in 1905; it was more than a match for Chiang Kai-shek. The only problem was, there was never any place to stop. Every step led to another step, until (like Germany invading Russia) Japan found itself fully committed in an invasion of a much larger country that it could never hope to occupy. And the more it forced itself upon hapless China, the more it became seen as a force that might menace others. The fact that it had joined Germany and Italy as part of the Axis only made it seem the more threatening. (There is comedy amid tragedy. One such touch: The racist Germans, respecting and needing the Japanese, termed them, presumably with a straight face, “honorary Aryans.”)
Inter-war Britain and France were in no mood to look for another enemy when they were so seriously threatened by the rise of Nazi Germany and, earlier, fascist Italy. They offered no opposition to Japan’s imperialist expansion, particularly its attacks on China. American isolationism was too strong for President Roosevelt to do much, whatever his inclinations. Mostly – until mid-1941 – he confined himself to words. But then, at almost the same time as the German invasion of the Soviet Union, delivered an ultimatum. Japan would cease its incursions on Chinese sovereignty or the United States would impose an embargo on oil and steel exports.
If this was meant to bring the Japanese to heel, it backfired. If it was meant to bring them to provoke a war in which they could be easily crushed, it backfired. What it provoked was the naval air assault on Pearl Harbor at dawn, December 7, 1941. That catastrophic morning, although no one knew it at the time, was the end of the era of surface fleets. The Japanese attack sent battleships to the bottom of the harbor, but it missed American aircraft carriers, which were out to sea on maneuvers, and it missed the submarines and the oil tanks holding the fuel that submarines burned. America defeated the Japanese Navy with the equivalent of U-Boats and Luftwaffe, combined with the capture of strategic islands for the sake of the bases they could provide for land-based bombers and fighters. In the end, America defeated Japan without ever landing an American soldier on Japanese soil (unless one counts Okinawa as Japanese soil, as Japanese do). Submarines sunk the shipping it needed not only to supply its overseas bases but to transport food to the home islands. Carrier-based airplanes fire-bombed Tokyo and other cities. Finally Okinawa-based B29s destroyed much of Hiroshima and Nagasaki with one bomb apiece – the atomic bomb that would bedevil the world thereafter.