After war was declared between the United States and Japan in December, 1941, the United States became China's ally but could not send military aid on the large scale needed. Japanese officials justified their conquests by claiming that Japan was liberating Asia from Western imperialism and that Westerners were racist and exploitative. A high official in the U.S. Department of State warned that "the Chinese are becoming increasingly disappointed and resentful" and that some Chinese were "beginning to talk of the possibility of China ceasing to be an active belligerent..." Former U.S. Secretary of State Cordell Hull, although not in the inner circle on policy toward China, turned his attention to negotiating a treaty to end the privileges granted over the previous century. The treaty was ratified by the United States Senate unanimously and came into effect on 20 May 1943.
In Chongqing, China's wartime capital, Generalissimo Chiang Kai-shek declared that with the signing of the treaties, "an independent China on equal footing" has become "a real friend" of Great Britain and the United States. Henceforth, Chiang concluded, "if we are weak, if we lack self-confidence, the fault will be ours." The official press praised Chiang. One newspaper said that the treaties made the Unequal Treaties into no more than "a stack of waste paper," and bragged that if it were not for our Party and for Sun Yat-sen and Generalissimo Chiang the treaties would still be in force. The leftist and communist press reacted quickly. They praised the efforts of the Communist Party in creating the United Front and claimed that the party had been a leader in the struggle for national liberation.
In December, 1943, in response to some of the same pressures which brought about the end of extraterritoriality, the Senate passed the Chinese Exclusion Repeal Act which ended the formal and legal exclusion of Chinese from immigration to the United States.