The Long Telegram was a pivotal 8,000-word message sent by U.S. diplomat George F. Kennan from Moscow to Washington in 1946, outlining his analysis of Soviet behavior and advocating for a policy of containment. This document significantly shaped U.S. foreign policy during the early Cold War, as it described the Soviet Union as a highly expansionist power that posed a direct threat to democracy and capitalism. The Long Telegram highlighted the growing tensions following the Yalta Conference and helped define the ideological struggle between the U.S. and the USSR.