In November 1945, Eisenhower returned to Washington to replace Marshall as Chief of Staff of the Army. His main role was rapid demobilization of millions of soldiers, a slow job that was delayed by lack of shipping. Eisenhower was convinced in 1946 that the Soviet Union did not want war and that friendly relations could be maintained; he strongly supported the new United Nations and favored its involvement in the control of atomic bombs. However, in formulating policies regarding the atomic bomb and relations with the Soviets, Truman was guided by the U.S. State Department and ignored Eisenhower and the Pentagon. Indeed, Eisenhower had opposed the use of the atomic bomb against the Japanese, writing, "First, the Japanese were ready to surrender and it wasn't necessary to hit them with that awful thing. Second, I hated to see our country be the first to use such a weapon." Initially, Eisenhower was characterized by hopes for cooperation with the Soviets. He even visited Warsaw in 1945. Invited by Bolesław Bierut and decorated with the highest military decoration, he was shocked by the scale of destruction in the city. However, by mid-1947, as East–West tensions over economic recovery in Germany and the Greek Civil War escalated, Eisenhower gave up and agreed with a containment policy to stop Soviet expansion.