Concept and Gaddis's explanation
Gaddis (1986) observed that although the Cold War was full of tension and proxy wars, more than four decades had passed since 1945 without direct war among the great powers, a longer stretch than the peace after the Napoleonic Wars or before World War I. As causes he cited the geographic distance and economic independence of the two superpowers, which offered few occasions for conflict; the simple structure of bipolarity; the deterrent effect of nuclear weapons; advances in reconnaissance that let each side know the other's capabilities; and the implicit rules of the game by which each side respected the other's sphere of influence.
Structural and normative explanations
The neorealist Waltz (1964) had argued early on that a bipolar system, in which two great powers need watch only each other, is more stable than a multipolar system prone to miscalculation. Mearsheimer (1990) attributed the long peace to bipolarity, a military balance and nuclear weapons, and predicted that Europe could become unstable again after the Cold War. These explanations rest on neorealism and deterrence theory. Mueller (1989), by contrast, argued that after two world wars the view that great-power war is horrible and futile spread widely in developed countries, sustaining the peace. Pinker (2011) interpreted the long peace as part of a broad historical decline in violence. The democratic peace and economic interdependence are offered as complementary explanations.
Statistical critiques
Whether the long peace reflects a structural change has also been questioned. Cirillo and Taleb (2016) argued that because war casualties follow a fat-tailed distribution in which extreme events are rare but enormous, several decades without a major war are insufficient to conclude that the risk of war has fallen. Analyzing interstate wars since 1823, Clauset (2018) reported that the current long peace is consistent with what could arise by chance under the same war-generating process as in the past, and that a much longer period would be needed to be confident of a change in trend. The long peace is thus an important subject of debate about the sources of international stability and how to assess the risk of future war.
FAQ
- What is the long peace in simple terms?
- It is the long period after World War II in which great powers such as the United States and the Soviet Union did not fight each other directly. Even during the Cold War, no major war broke out between great powers.
- Will the long peace continue?
- Opinions differ. Some argue it will last thanks to nuclear deterrence and changing norms, while statistical critics note that because major wars are rare, a few decades of peace cannot prove that the risk has declined.
Sources reviewed: 2026-10-26
References
- Gaddis, J. L. (1986). The long peace: Elements of stability in the postwar international system. International Security, 10(4), 99–142. The article that coined the term — Gaddis's original explanation of postwar stability.
- Waltz, K. N. (1964). The stability of a bipolar world. Daedalus, 93(3), 881–909. The classic argument that bipolarity is stable — the structural explanation's roots.
- Mearsheimer, J. J. (1990). Back to the future: Instability in Europe after the Cold War. International Security, 15(1), 5–56. Predicted post-Cold War instability — attributes the peace to bipolarity and nuclear weapons.
- Mueller, J. (1989). Retreat from Doomsday: The Obsolescence of Major War. New York: Basic Books. Argues changing attitudes, not nukes, made major war obsolete — the normative view.
- Pinker, S. (2011). The Better Angels of Our Nature: Why Violence Has Declined. New York: Viking. Places the long peace within a broad decline of violence — the optimistic case.
- Cirillo, P., & Taleb, N. N. (2016). On the statistical properties and tail risk of violent conflicts. Physica A: Statistical Mechanics and its Applications, 452, 29–45. A statistical rebuttal: fat-tailed war sizes make short peaceful periods weak evidence.
- Clauset, A. (2018). Trends and fluctuations in the severity of interstate wars. Science Advances, 4(2), eaao3580. Tests whether the long peace could be a chance fluctuation using data since 1823.