BBC History Magazine
“There was little room for diplomacy in Japan’s increasingly extreme world view”
Why did the US not discover the plan to attack Pearl Harbor before it was too late? By December 1941, American decrypting machines were cracking the code used to send messages between Tokyo’s Foreign Ministry and Japanese embassies around the world. But the Foreign Ministry was unaware of the specifics of the Pearl Harbor plan – it had been cooked up within the Navy Ministry. The US simply didn’t get hold of the right intelligence in time.
Here was a rare example of the divisions inside Japan’s power structures working in the country’s favour. Across the 1930s and into the 1940s, factions in Japan’s politics, bureaucracy and military fought viciously over their country’s place in the world, with the most extreme points of view steadily winning out: Japan as a century-long victim of grasping, white western imperialism; Japan now fatally encircled by those powers and their east Asian allies.
There was little room for diplomacy in a world view like this. Instead, an unwinnable but unstoppable war was launched in China, at the cost of 20 million Chinese lives and the poisoning of relations with America to the point where Pearl Harbor became inevitable – not as grand strategy, but as a desperate attempt to escape the quagmire created by Japan’s divided leadership. On these terms, Pearl Harbor was a perverse success: within a few years, American anger would force an apocalyptic wiping clean of the slate.