How did U.S. economic sanctions against Japan contribute to the Pearl Harbor attack?

U.S. economic sanctions were a primary catalyst for the Pearl Harbor attack because they threatened Japan’s ability to sustain its military and industrial economy.

Following Japan’s occupation of Indochina in July 1941, the United States responded by freezing Japanese assets and imposing a total embargo on petroleum and other vital war materials. Because Japan’s domestic stockpiles were inadequate, this cutoff presented the Japanese government with a stark choice: either withdraw from China and Indochina to appease the U.S. or seize alternative resource-rich territories, such as the Dutch East Indies, to secure necessary supplies.312

The Japanese military, already influential in the government, viewed the embargo as an existential threat. They concluded that war with the United States and Great Britain was inevitable unless diplomatic negotiations yielded a reversal of these sanctions. When negotiations failed to produce an agreement—largely due to U.S. demands for a full Japanese withdrawal from China—Japan’s leadership decided to neutralize the U.S. Pacific Fleet at Pearl Harbor to clear the way for unhindered conquest in Southeast Asia.314