Tensions between the U.S. and Japan were already at historic highs when Japan began marching through China, occupying parts that belonged to France, itself under German occupation. The U.S. had already cut off trade with the other Axis powers, and Japan’s aggressive stance, bringing it uncomfortably near the Philippines, made President Roosevelt decide to cut off Japan as well. Just weeks after the Germany’s trade with Japan was cut off with the German invasion of Russia, with a single stroke of a pen Roosevelt eliminated the last of Japan’s major trading partners.

On this day, July 26, in 1941, President Roosevelt signed an Executive Order freezing all Japanese assets held in the U.S,. and cutting off trade. As the June 14 order against Germany, this one was intended to “prevent the use of the financial facilities … and trade between Japan and the United States, in ways harmful to national defense and American interests.”

The U.S. also feared internal subversion. During the Pearl Harbor attack four months later, a Japanese pilot shot down over the island of Ni’hau was aided by several islanders of Japanese descent. Although he never managed to escape and was stopped by several other islanders, it gave the U.S. government backing to go beyond the freezing of assets and round up American citizens with Japanese roots into specially-designated camps for the duration of the war.