11.1The Cold War begins

The wartime alliance with the Soviet Union collapsed almost immediately into rivalry. The United States and the USSR represented opposing systems—democratic capitalism versus one-party communism—and each sought to expand its influence. Rather than fight directly, the superpowers waged a "cold" war of ideology, espionage, proxy conflicts, and a terrifying nuclear arms race.

American strategy centered on "containment": preventing communism's spread. This produced the Marshall Plan to rebuild Western Europe, the NATO alliance, and a permanent peacetime military establishment. Fear of communism also gripped domestic politics, fueling the anti-communist crusades associated with Senator Joseph McCarthy, which ruined careers and stoked suspicion. The Cold War would shape American life for over forty years.