Faced with choosing between British interests and Iran, the U.S. chose Britain, Gasiorowski said. "Britain was the closest ally of the United States, and the two countries were working as partners on a wide range of vitally important matters throughout the world at this time. Preserving this close relationship was more important to U.S. officials than saving Mosaddeq's tottering regime." A year earlier, British Prime Minister Winston Churchill used Britain's support for the U.S. in the Cold War to insist the United States not undermine his campaign to isolate Mosaddegh. "Britain was supporting the Americans in Korea, he reminded Truman, and had a right to expect 'Anglo-American unity' on Iran."