On the eve of World War II, he helped alert President Franklin D. Roosevelt that Germany might be developing an atomic weapon and recommended that the U.S. begin similar research; this eventually led to what would become the Manhattan Project.
On the eve of World War II, he endorsed a letter to President Franklin D. Roosevelt alerting him to the potential developing of "extremely powerful bombs of a new type" and recommending that the U.S. begin similar research. This eventually led to what would become the Manhattan Project.