The Truman Doctrine speech was heavily influenced by the geopolitical environment and crises of the early Cold War. In August 1945, British Prime Minister Winston Churchill, Soviet General Secretary Joseph Stalin, and American President Harry Truman met at Potsdam, in what was then occupied Berlin. The leaders of the allied nations met with the purpose of discussing how to establish a lasting postwar peace, but their widening divide was becoming increasingly clear. The US had successfully tested the atomic bomb, while Russia was exerting influence in Eastern Europe to create communist-run satellite states. The actions of each superpower began to increase suspicion and hostility between them, with Truman viewing the Soviet control of Eastern Europe as expansionism and the Soviets feeling threatened by the American wish to rehabilitate German industry. The conditions for the Cold War which would dominate geopolitics for the next half-century had already begun to form.

Many leading statespeople and commentors recognized the increasing polarization of Europe, as exemplified through speeches such as Winston Churchill’s “Iron Curtain” speech and George Kennan’s “Long Telegram/Article X” publication. These both pointed out the division of Europe into Soviet and non-Soviet zones and warned that Russia would seek to spread communist ideology.