“A date which will live in infamy” — but was Pearl Harbor a surprise attack or a foreseen war with a surprising address?

THE SHORT ANSWER

• The oil clock ran out. From the August freeze (Ch. 10), Japan’s planners calculated capability declining monthly; the Imperial Conference of 6 September set the sequence — negotiate until October, then decide for war. Konoe’s government fell seeking a summit Washington wouldn’t grant without prior concession on China; Tōjō’s government inherited the timetable. The Hull note of 26 November was the formal end of the diplomatic road, but the fleet had sailed that morning: the machine was running on fuel arithmetic, not on the last exchange of documents.
• Yamamoto’s wager against his own judgment. The Combined Fleet commander had told Konoe he could “run wild for six months or a year,” with no confidence thereafter — he knew America (Harvard, naval attaché in Washington) and opposed the war his plan enabled. His logic for Pearl Harbor was conditional: if war is forced, the US battle fleet must not be free to interdict the southern operation; a stunning opening blow might also break American will to fight a long war. The first premise was operationally sound; the second inverted the country he knew — and he suspected as much. Planners who brief “six months” should be asked, as history asked Yamamoto, what happens in month seven.
• Washington expected war — somewhere else. American commanders knew from decrypts (MAGIC) that war was imminent; the war warnings of 27 November went to all Pacific commands. The failure was of imagination and correlation: the Philippines and Malaya were the obvious targets; Pearl Harbor was judged too far, too shallow for torpedoes (Taranto’s lesson, Ch. 11, had been studied more carefully in Tokyo than in Hawaii), too audacious. Radar on Oahu detected the first wave 132 miles out; the duty officer read it as a flight of B-17s due from California. Surprise is rarely a failure to collect information; it is a failure to believe it.
• Hitler chose the world war. Nothing obliged Germany to declare war on America on 11 December — the Tripartite Pact covered only a Japan attacked. Hitler’s reasoning, reconstructed from his 11 December Reichstag speech and table talk: the U-boat war against American convoys was already undeclared war; Japan would pin the US in the Pacific for years; and racial-ideological contempt for a “mongrel” nation misjudged, one last time, an adversary’s capacity. It was the decade’s final unforced gamble, and it unified the two wars this atlas has kept on separate maps into the one its title promised.

WHAT IT CHANGED

The perimeter, then the tide. Japan’s six months ran almost exactly to Yamamoto’s schedule: Malaya, Singapore (the empire’s worst capitulation, February 1942), the Indies and the Philippines all fell. Then Coral Sea checked the advance in May 1942, and at Midway in June the carriers missed at Pearl sank four of the six that had attacked it. The war this atlas ends by starting is told in the WW2 atlas — this map hands its final snapshot to that one’s first.

The arsenal opens both doors. Germany’s declaration let Roosevelt pursue “Europe first” with public consent. Lend-Lease, already flowing to Britain and the USSR, became the bloodstream of a global coalition. By war’s end it had supplied some $50 billion in matériel. That aid ranged from Studebaker trucks on the road to Moscow to the food shipments that kept Britain fed.

Asia’s empires never come back. The tan on this map’s southern half did not survive the demonstration that European empires could be beaten by an Asian power in weeks. The colonial restorations of 1945 were rearguard actions; India was gone by 1947, Indonesia by 1949, Indochina after wars that fill the Cold War atlas. Japan’s war of conquest, defeated, still ended the world it attacked.