As the Year of the Dragon (1940) gave way to the Year of the Snake (1941), the United States and Japan appeared on a collision course toward war. The Japanese had a name for the crisis: Taiheiyo-no-gan – Cancer of the Pacific. The issues that pushed the two nations toward military confrontation were many, but their source was simple: Japan sought security and equality and saw this goal as being blocked by the United States and the European colonial powers and their embargoes.

It could be argued that the crisis had its origin in an incident that occurred almost a century earlier. In 1858, Commodore Matthew Perry’s East India Squadron arrived in Tokyo harbor. The visit shocked Japan. Within 50 years, the country transformed itself from a feudal agrarian society into a modern industrial powerhouse. And, with its defeat of Imperial Russia in 1905 in the Russo-Japanese War, Japan became a world power.

But Japan’s breathtaking rise had two important consequences, one emotional and the other practical. Japanese leaders resented Western nations’ patronizing of the “clever” Japanese. More importantly, the rapid industrialization revealed a crucial weakness affecting national growth and security: Japan was a heavily populated country barely capable of feeding itself and bereft of natural resources vital for industry. Maintaining the status quo of importing from the West the raw materials and commodities it needed would lock Japan into a dependent role with the United States and other Western nations rich in foodstuffs and natural resources. To ultranationalists who had risen to power in the 1930s such a position of inferiority was intolerable. In addition to military parity, they sought to replace Western presence in the Pacific Rim with the Greater East Asia Co-Prosperity Sphere, a vaguely defined economic military defense bloc dominated by Japan.

The first step in their expansionist policy occurred in 1931 when Japan wrested from China the resource-rich northern province of Manchuria and made it the puppet state Manchukuo. In 1937 it invaded north China. Two years later, its armies attacked south China. In September 1940, Japan formally linked its future to the Axis powers of Germany and Italy by signing the Tripartite Pact alliance. In that same month, Japan forced the pro-Nazi Vichy French government to accept its military occupation of French Indochina. At the same time, American civilians and military forces stationed in China endured provocative attacks and interferences with their rights and interests.

America, first under President Herbert Hoover and then Franklin D. Roosevelt initially responded with diplomatic protests. When they failed to curb Japanese aggression, Roosevelt upped the ante. In 1938, the State Department advised banks at home and abroad not to extend credit to Japanese businesses. In 1939, the United States terminated the 1911 commercial treaty between the United States and Japan. This led to an American embargo initially of airplanes, parts, machine tools, and aviation gasoline. The embargo was expanded in 1940 to include oil, iron and steel scrap, and other commodities. Sharing America’s concerns, Great Britain and the Netherlands joined in the economic embargo.

Japanese leaders had already done the math, and the numbers were ugly. If the situation remained unchanged, Japan faced economic ruin within two years. But for the West to lift the embargo, Japan had to retreat from China and abandon its expansionist policy – a surrender pill too bitter and humiliating for the far right to swallow. On Jan. 23, 1941, Japan sent ambassador Adm. Kichisaburo Nomura, respected in America, to the United States in a final effort to lift the embargo. It was a smoke screen. No one expected his mission to succeed.

Adm. Isoroku Yamamoto, commander in chief of the Imperial Japanese Combined Fleet, was a patriot, not a jingoistic ultranationalist. Disgusted by the far right’s saber rattling, on Jan. 26, 1941, he wrote a letter to a prominent member, Ryoichi Sasakawa. In it, Yamamoto warned, “Should hostilities break out between Japan and the United States, it would not be enough that we take Guam and the Philippines, or even Hawaii and San Francisco, [California]. To make victory certain, we would have to march into Washington [D.C.] and dictate the terms of peace in the White House. I wonder if our politicians, among whom armchair arguments about war are being glibly bandied about in the name of state politics, have confidence as to the final outcome and are prepared to make the necessary sacrifices.” That paragraph, with the last sentence deleted, was made public, transforming the author’s cautionary message into a nationalistic boast.

But by the time the altered document was made public Yamamoto could not correct the record. His government had made its decision: war. Ironically, he would be a lead architect in it.