Einstein, in a ceremony in Trenton, N. J., became a U.S. citizen on October 1, 1940. Alarmed by the news that Germany had successfuly split a uranium atom, he had swallowed his pacifism a year earlier to urge President Franklin Roosevelt to step up U.S. development of an A-bomb. Einstein would actively support the Allies' war against fascism by working as a weapons consultant for the U.S. Navy.

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