<P> Beginning in 1938 , the U.S. adopted a succession of increasingly restrictive trade restrictions with Japan . This included terminating its 1911 commercial treaty with Japan in 1939 , further tightened by the Export Control Act of 1940 . These efforts failed to deter Japan from continuing its war in China , or from signing the Tripartite Pact in 1940 with Nazi Germany and Fascist Italy , officially forming the Axis Powers . </P>
when did the us stop trading with japan
1939