"[May-Johnson is] the first totalitarian bill ever written by Congress. You can call it a Communist bill or a Nazi bill, whichever you think is worse."

Harold Urey. "Dr. Urey Excoriates Atom Bill," New York Times. October 31, 1945.

"Most scientists think wars and national boundaries are a menace to the true creative spirit by which science must live, they hate war and they are terrified of atomic war –- because they know its possibilities."

Harold Urey. "I’m A Frightened Man," as told to Michael Amrine, Colliers. January 5, 1946.

"Today we are engaged in a contest for human freedom. During the last war we crushed one type of totalitarian tyranny in a military sense, but the ideological fight has not been won, for we cannot eliminate ideas by physical means and yet maintain freedom of thought. Only better and more inspiring ideas can be used to fight tyrannical ideas."

Harold Urey. "Atomic Energy: How to Control It," California Monthly. December 1947.