In This Article Expand or collapse the "in this article" section NATO

  • Introduction
  • General Overviews
  • International Relations Theory and NATO
  • Cold War History
  • Post-Cold War and 9/11 Adaptation, Transformation, and Endurance
  • Institutional Structure
  • NATO Military Organization, Strategy, and Policy
  • Nuclear Weapons and Deterrence
  • “Out of Area” Operations
  • Enlargement
  • Partnership
  • NATO-EU and Other Inter-Institutional Relations
  • NATO–Russia Relations
  • Primary Sources

Military History NATO
Seth Johnston
  • LAST REVIEWED: 31 July 2023
  • LAST MODIFIED: 28 July 2021
  • DOI: 10.1093/obo/9780199791279-0206


The North Atlantic Treaty Organization (NATO) is a military alliance and international organization comprising North American and European countries. It is generally considered to be among the most powerful, long-enduring, and successful alliances of modern times. It has influenced both the study and practice of international security and politics for more than seventy years. Created in 1949 by twelve countries as a classic treaty-based mutual defense pact, its substantive focus, formal organization, and membership grew steadily from its earliest years. The legacy of World War II and the trials of the Cold War dominated NATO’s first four decades, when the organization’s first secretary general described its purposes for Europe as keeping “the Americans in, the Russians out, and the Germans down.” The 11 September 2001 terrorist attacks accelerated the post–Cold War transformation of NATO’s political and military functions. Yet the central issue in politics among the allies has often been the “burden sharing” or distribution of costs and benefits. The United States, France, Germany, and the United Kingdom have often wielded outsized roles in such politics, though NATO decisions are taken by consensus traditionally. The endurance of NATO after the Cold War and through many crises is one of the great puzzles in the academic discipline of international relations, and the Alliance is a common object of study in all the main theoretical schools of thought. While NATO’s political structures resemble other international organizations, its standing multinational integrated military structure is unique. Its military policy and strategy evolved with thinking about deterrence in the nuclear age. NATO first embarked on “out-of-area” military operations in the Balkan civil wars of the 1990s, but its largest and longest-running mission began in 2003 with its involvement in Afghanistan, far from its original geographic area of concern. NATO has entered into political and military partnerships with dozens of countries around the world, and its enlarged membership reached thirty countries in 2020. Its global ties add to a longer-standing debate about trans-Atlanticism versus autonomy in European security. NATO and the European Union give important context to one another, though their institutional collaboration has not always been as close as their greatly overlapping membership and neighboring headquarters in Belgium might suggest. Russia’s invasion of Ukraine in 2014 inaugurated a period of increased tension with NATO, though the Alliance has alternated deterrence and dialog in its relations with Russia both during and since the Cold War. Primary sources and archival material about NATO are increasingly accessible.

General Overviews

A thorough and up-to-date single overview, Sloan 2020 is the latest of many books by the longtime observer and champion of the Alliance. Primary source documents and scholarly commentary in Shapiro and Tooze 2018 complement any good overview. Kaplan 2004 and Yost 2014 set high standards for detail and authoritativeness in an essential history and analysis of contemporary issues in the alliance. Deni 2017 underscores NATO’s renewed emphasis on collective defense since Russia’s invasion of Ukraine in 2014. Lute and Burns 2019 and Tardy 2020 offer up-to-date practitioner perspective in policy-relevant papers following NATO’s seventieth anniversary. NATO 2030 follows a long Alliance tradition of turning to an independent group of experts for ideas about the future.

  • Deni, John R. NATO and Article 5: The Transatlantic Alliance and the Twenty-First-Century Challenges of Collective Defense. Lanham, MD: Rowan & Littlefield, 2017.

    A recent assessment reflecting the rebalancing of allies’ attention to collective defense since 2014.

  • Kaplan, Lawrence S. NATO Divided, NATO United: The Evolution of an Alliance. London: Praeger, 2004.

    A history introducing recurring themes in transatlantic Alliance relations, by the distinguished authority on NATO history.

  • Lute, Douglas, and Nicholas Burns. NATO at Seventy: An Alliance in Crisis. Report, Belfer Center for Science and International Affairs. Cambridge, MA: Harvard Kennedy School, February 2019.

    A widely cited analysis of contemporary challenges, including novel coverage of China and cyber, from two former US ambassadors to NATO. Richly footnoted.

  • NATO 2030: United for a New Era. Brussels: North Atlantic Treaty Organization, 25 November 2020.

    Report of an independent expert group commissioned by the Alliance with 138 specific recommendations. Comparable reports informed some of NATO’s past strategic concepts.

  • Shapiro, Ian, and Adam Tooze, eds. Charter of the North Atlantic Treaty Organization. New Haven, CT: Yale University Press, 2018.

    Curated primary source documents with commentary by respected scholars. Emphasizes NATO’s early history and post–Cold War period, excluding mid-Cold War era documents such as the Harmel Report.

  • Sloan, Stanley R. Defense of the West: Transatlantic Security from Truman to Trump. 2d ed. Manchester, UK: Manchester University Press, 2020.

    Latest edition of perhaps the best single up-to-date text on the Alliance and its history, from one of its most experienced and expert observers.

  • Tardy, Theirry, ed. “NATO at 70: No Time to Retire.” NDC Research Paper No. 8. Rome: NATO Defense College, January 2020.

    Leading practitioners and NATO insiders argue strongly for the Alliance and its prospects in a collection of essays.

  • Yost, David S. NATO’s Balancing Act. Washington, DC: United States Institute of Peace, 2014.

    Detailed assessment of NATO’s three self-described “core tasks”—collective defense, crisis management, and cooperative security—written just before Russia’s invasion of Ukraine.

back to top

Users without a subscription are not able to see the full content on this page. Please subscribe or login.

How to Subscribe

Oxford Bibliographies Online is available by subscription and perpetual access to institutions. For more information or to contact an Oxford Sales Representative click here.