President Harry S. Truman Announcing the First Atomic Explosion by the USSR

September 23, 1949

The American people, to the fullest extent consistent with national security, are entitled to be informed of all developments in atomic energy. That is my reason for making public the following information. We have evidence of an atomic explosion in the U.S.S.R. in recent weeks.

Ever since man first released atomic energy, the eventual development of this new force by other nations was to be expected. This probability has always been taken into account by us.

Nearly four years ago, I pointed out that “scientific opinion appears to be practically unanimous that the essential theoretical knowledge upon which the discovery is based is already widely known. There is also substantial agreement that foreign research can come abreast of our present theoretical knowledge in time.” And in the Three-Nation Declaration of the President of the United States and the prime ministers of the United Kingdom and of Canada, dated November 15, 1945, emphasized that no single nation could have a monopoly on atomic weapons.

This recent development emphasizes once again, if indeed such emphasis were needed, the necessity for that truly effective, enforceable international control of atomic energy, which this Government and the large majority of the members of the United Nations support.

Source: Public Papers of the President of the United States: Harry S. Truman, 1949 (Washington, D.C.: GPO, 1964), 485.