The term "Long Peace" was popularized by historian John Lewis Gaddis in a 1986 International Security article and developed further in his 1987 book The Long Peace: Inquiries Into the History of the Cold War. Gaddis used it to describe the striking fact that, despite ideological hostility between the United States and the Soviet Union, the two superpowers never fought each other directly, and no war occurred between major powers after 1945 — a stretch unprecedented in the modern state system.
Scholars have offered several explanations for why this period was relatively peaceful at the great-power level:
- Nuclear deterrence, including the doctrine of mutually assured destruction, raised the expected cost of direct conflict to prohibitive levels.
- Bipolarity, as argued by Kenneth Waltz, simplified the calculation of threats and made miscalculation less likely than under multipolarity.
- Economic interdependence and institutionalization through bodies such as the UN, NATO, the Warsaw Pact, GATT, and Bretton Woods institutions created channels for managing disputes.
- Norms against territorial conquest strengthened after the UN Charter (1945) prohibited the use of force except in self-defense or under Security Council authorization.
The concept is contested. Critics note that the Long Peace coexisted with devastating proxy wars in Korea, Vietnam, Afghanistan, Angola, and Central America, and with mass violence in decolonization conflicts. Steven Pinker, in The Better Angels of Our Nature (2011), extended the idea statistically, arguing that interstate violence has declined more broadly. Others, including Bear Braumoeller in Only the Dead (2019), challenge that claim on methodological grounds.
For IR students, the Long Peace is a central case in debates over realism versus liberalism, the stabilizing or destabilizing effects of nuclear weapons, and whether great-power war has become obsolete. Renewed tensions involving Russia, China, and the United States have reopened the question of whether the Long Peace is durable or a historical anomaly tied to specific Cold War conditions.
Example
When debating nuclear posture in 2023, analysts often cited the Long Peace to argue that US–Soviet deterrence after 1945 prevented a third world war despite proxy conflicts in Korea and Vietnam.
Frequently asked questions
Historian John Lewis Gaddis popularized it in a 1986 article in International Security and his 1987 book The Long Peace: Inquiries Into the History of the Cold War.
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