The act originated as a presidential proclamation by Roosevelt forbidding the exporting of aircraft parts, chemicals, and minerals without a license, and it was intended to induce Japan to curtail its occupation of the coast of Indochina.
[2] The text stated that whenever the President deemed it "necessary in the interest of national defense," he could prohibit or curtail the exportation of military equipment, munitions, tools, and materials.
That is exemplified by the restrictions on export of certain strategic or military items to the Soviet bloc or to other countries that it felt, if permitted, would be detrimental to US foreign policy during the Cold War.
The foreign policy motive became so strong that it brought legislation directing the president to enlist the co-operation of other nations in enacting controls on trade with the Soviet block to parallel those of the United States.
[11] After World War II, the Export Control Act was expanded to prevent the diversion of advanced technology to the Soviet bloc and China and, in later years, to alter the behavior of foreign countries.
[16] The last motive became so strong that it brought legislation directing the president to enlist the co-operation of other nations in enacting controls on trade with the Soviet block to parallel those of the United States.