than a mere justification to open hostilities against Japan that American contin- ued to insist that Japan secede from the Axis Alliance in the Hull Note in the final stage of the Japan-United States talks.
This conclusion of this thesis that the problem of secession from the Axis Alliance was no more than a pretext for America's participation in the Pacific War tallies with P.W. Schroeder's view. But it seems that P.W. Schroeder, an American historian, does not lay much stress on the importance of the United States-Soviet rapprochement, which took place after the outbreak of the Ger- man-Soviet War.
Accordingly, the present writer has tried to make clear in this thesis that the change in international politics, namely, the realization of a cooperative rela- tionship between the two superpowers, the United States and Russia, was a fun- damental cause of America's firm policy toward Japan, taking a serious view of the impact exerted on world politics by the outbreak of the German-Soviet War, which made the proposed Japan-Germany-Italy-Soviet four-power alliance a dead letter, and particularly, the United States-Soviet rapprochement immedi- ately after the outbreak of the German-Soviet War.
To repeat, the outbreak of the German-Soviet War and the German mili- tary successes in the initial stages of the war when the German army held an overwhelmingly superior position made America foresee Germany seizing con- trol of Europe and the fall of Britain and realize that in that event, not only would Western democracy be destroyed, but also that America's own national security would be threatened.
For this reason, President F.D. Roosevelt embarked on rapprochement with Soviet Russia, concluding that it was an urgent business to control Ger- many by giving aid to Russia, without sticking to ideology.
Once the way was opened for United States-Soviet rapprochement, it be- came quite unnecessary for America to appease Japan, as she did in the initial stage of the Japan-United States negotiations. Thus, America could solidify the foundation for her firm policy toward Japan.
When the situation at that time is observed from the viewpoint of change in international relations after the outbreak of the German-Soviet War and America's way of coping with them, I believe that the circumstances under which America employed a firm policy toward Japan in the latter half of 1941 can be understood in its true context.
What were the origins of the United States' strong measures against Japan