In This Article Expand or collapse the "in this article" section Peacekeeping in International Law

  • Introduction
  • General Works on Collective Security and United Nations Law
  • General Works on Peacekeeping Law
  • Consent and Impartiality
  • Self-Defense/Use of Force
  • Peacekeeping Development and Reform
  • Complex Peace-Building and State-Building Operations
  • Human Rights Law and Peacekeeping
  • Protection Mandates
  • International Humanitarian Law and Peacekeeping
  • Regional Peacekeeping
  • The Role of Private Contractors
  • Responsibility
  • Accountability

International Law Peacekeeping in International Law
Nigel D. White
  • LAST REVIEWED: 12 April 2019
  • LAST MODIFIED: 28 November 2016
  • DOI: 10.1093/obo/9780199796953-0015


Peacekeeping is a development of the Cold War and a creation largely of the United Nations. The deployment of such forces was not envisaged by the UN Charter of 1945, but peacekeeping has proved vital in securing a minimum level of peace and security in trouble spots around the world. Although new in its day, the “traditional” type of peacekeeping force first deployed in Suez in 1956 reflected traditional, or classical, principles of international law in that it was based on the consent of the host state or states, and even though it appeared to constitute military intervention, its respect for sovereignty was reflected in the neutrality of such forces. The trinity of peacekeeping principles of consent, impartiality, and nonuse of aggressive force very much reflected those fundamental principles of international law—of sovereignty, nonintervention, and nonuse of force found in Article 2 of the UN Charter. However, Article 2 (paragraph 7) and Chapter VII (Article 42) of the UN Charter both recognize that the UN Security Council (UNSC) has exceptional powers to undertake enforcement action, which has led to, on occasions, peacekeeping forces being given more coercive mandates. The dialectic between consensual peacekeeping and its more belligerent variant was established as early as the second full peacekeeping force in the Congo in 1960–1964, and it is currently back on the agenda as the United Nations struggles to implement the “protection of civilians” agenda through coercive mandates given to UN forces. Coercive mandates mean that peacekeepers are increasingly crossing the line to become war fighters, or “combatants” in the language of international humanitarian law, causing confusion as to the legal status of peacekeepers, who are traditionally not seen as legitimate targets; indeed, attacks on them remain prohibited. Even consensual post–Cold War peacekeeping has moved away considerably from the traditional buffer forces of the Cold War, evolving in the early 1990s toward complex civilian-military operations designed to build the peace as well as to keep it, and including within its structure military, police, humanitarian, and other civilian elements. A vast amount of literature exists on peacekeeping, a significant part of which is listed in the Oxford Bibliographies in International Relations article “Peacekeeping” by Erik K. Rundquist. The focus here is on the legal aspects of peacekeeping, and the overlap with the bibliography by Rundquist is kept to a minimum.

General Works on Collective Security and United Nations Law

It is not possible to understand the legal evolution of peacekeeping without first positioning it within the wider framework of the UN Charter, collective security law, and also international law governing the use of force. The literature in these areas is extensive. This section includes a selection that will place the development of peacekeeping within this wider legal context. Blokker and Schrijver 2005 focuses on the role of the UN Security Council (UNSC), as does Lowe, et al. 2008. Simma 2012 is an essential reference work in considering the place of peacekeeping within the UN Charter, while Chesterman, et al. 2008 develops this legal framework by looking at peacekeeping within UN law as a whole. Kelsen 1957, Sarooshi 1999, Orakhelashvili 2011, and Tsagourias and White 2013 help place peacekeeping within the wider concept of collective security. Chetail 2009 places peacekeeping within the wider function of building peace and contains a variety of disciplinary perspectives.

  • Blokker, Niels M., and Nico Schrijver, eds. The Security Council and the Use of Force. Leiden, The Netherlands: Martinus Nijhoff, 2005.

    The development of so-called coalitions of the willing by the UNSC under Chapter VII is legally distinct from the development of peacekeeping. But both are military measures taken under UN authority, and this collection helps in understanding the differences and similarities between them.

  • Chesterman, Simon, Thomas M. Franck, and David M. Malone. Law and Practice of the United Nations. Oxford: Oxford University Press, 2008.

    A useful collection of documents and commentary on wider issues of UN law, many of which pertain to the legal framework within which peacekeeping operates—powers, financing, responsibility, and accountability. The work covers both peacekeeping and peacemaking.

  • Chetail, Vincent, ed. Post-Conflict Peace Building: A Lexicon. Oxford: Oxford University Press, 2009.

    A modern, interdisciplinary lexicon of peace-building concepts, such as capacity building, civil society, human security, local ownership, responsibility to protect, transitional justice, and many others (including a chapter on peace operations), reflecting wider normative frameworks within which peacekeeping forces operate. It is essential for a full understanding of modern peace operations.

  • Kelsen, Hans. Collective Security under International Law. Washington, DC: US Government Printing Office, 1957.

    This classic text analyzes the legal basis of both military and nonmilitary sanctions. Though written before the first full peacekeeping force, it still is one of the best depictions of the legal framework governing such operations.

  • Lowe, V., A. Roberts, J. Welsh, and D. Zaum, eds. The United Nations Security Council and War. Oxford: Oxford University Press, 2008.

    A somewhat wider collection than Blokker and Schrijver 2005 with a number of interesting chapters on peacekeeping and the Suez crisis within a broader range of conceptual chapters and case studies.

  • Orakhelashvili, Alexander. Collective Security. Oxford: Oxford University Press, 2011.

    DOI: 10.1093/acprof:oso/9780199579846.001.0001

    A comprehensive doctrinal classification and exposition of organizations, competences, and practice. A very useful reference work on collective security with significant coverage of peacekeeping.

  • Sarooshi, Dan. The United Nations and the Development of Collective Security: The Delegation by the UN Security Council of Its Chapter VII Powers. Oxford: Oxford University Press, 1999.

    Authoritatively discusses the delegation of powers by the UNSC to states, regional organizations, subsidiary organs, and the UN secretary-general (UNSG) and by doing so establishes a relatively clear legal framework within which such powers can be exercised.

  • Simma, Bruno, ed. The Charter of the United Nations: A Commentary. 3d ed. Oxford: Oxford University Press, 2012.

    The definitive article-by-article analysis of the UN Charter, the only exception being a separate contribution on peacekeeping by Michael Bothe, illustrating that peacekeeping has been developed in practice as an implied power belonging to both the UN General Assembly (UNGA) and the UNSC.

  • Tsagourias, Nicholas, and Nigel D. White. Collective Security: Theory, Law and Practice. Cambridge, UK: Cambridge University Press, 2013.

    DOI: 10.1017/CBO9781139058506

    Theoretical and normative frameworks for collective security are debated and identified. Within these frameworks, the parameters of collective security measures, including peacekeeping, are analyzed.

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