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International Law and the Use of Force (Module)

Module description


  • Induction and Orientation module
  • If studying War in the Modern World you must also complete History of Contemporary Warfare 1: the early Cold War, 1945–1975 and History of Contemporary Warfare 2: from Cold War to War on Terror, 1975-2011.
  • If studying International Relations and Contemporary War, you must also complete International Relations and Contemporary War 1: Theories and Concepts and International Relations and Contemporary War 2: Problems and Issues.

Study units

  • Law, War, Ethics and Crime
  • Collective Security and the UN System
  • Humanitarian Intervention and the Responsibility to Protect
  • Self-Defence
  • The Conduct of Contemporary War


International law is at the forefront of political, academic and public discourse about the use of force. This was increasingly evident in the decade following the end of the Cold War, when the Security Council acted with renewed vigour in situations they deemed to constitute a threat to international peace and security, including the 1991 Iraqi invasion of Kuwait, and subsequent Gulf War, and interventions in Somalia, Bosnia, and elsewhere.  Legal arguments featured increasingly prominently, in debates about whether the international community was in breach of its obligation to intervene to stop the genocide in Rwanda, and, conversely, whether NATO’s action against Serbia over Kosovo in the absence of explicit UNSC authorisation overstepped the boundaries of the law.

More recently, it has been evident in discussions about the United States and its allies response to the threat of global terrorism, the invocation of self-defence as justification for the invasion of Afghanistan and Iraq, the legitimacy of humanitarian intervention and the scope of a legal responsibility to protect civilians in Libya and Syria, and debates over the conduct of military operations, including allegations of misconduct, criticism of the treatment of detainees, and new technologies on the battlefield, such as unmanned systems (drones), all of which pose challenges to existing law, as does the potential displacement of the battlefield to cyberspace. 

Meanwhile, we have witnessed a halting, but seemingly irreversible trend toward a norm of accountability when the law is breached, exercised in domestic and international courts, and concerning the responsibility of individuals and that of the state.  Discussions of legality feature ever more prominently in public discourse on the use of force, with allegations of war crimes levelled against political leaders on all sides.  All of this has given rise to a need for a more systematic and thorough understanding of the relevant legal and ethical restraints on the use of force. This course is designed to provide a framework in which to discuss these important issues.

The module covers both international law governing the use of force (the jus ad bellum) and the way in which force is used – the conduct of war (jus in bello).  We begin with the evolution of ethical and legal restraints on the use of force, culminating in the prohibition on the use of force enshrined in the United Nations Charter in all but exceptional circumstances. Units 2, 3 and 4 consider the scope of these exceptions including those envisaged in the UN Charter (collective security and self-defence) and those that are not (humanitarian intervention).  In unit 2 we consider the meaning and application of collective security under Article 42 of the UN Charter, the evolution of peacekeeping from its inception to the large footprint peacebuilding missions of the late-1990s and the legal framework for the regulation of peace operations devolved to regional actors. In unit 3, we consider the evolution of the Responsibility to Protect and its application in Kosovo, Darfur, Iraq, Libya and beyond. In unit 4, we consider the scope and application of the right of self-defence, from traditional understandings and interpretations of Article 51 of the UN Charter to its application in a contemporary world faced with new and old threats of nuclear weapons proliferation, acts of terrorism and cyber-war.  Finally, in unit 5, we shift the focus to the jus in bello and consider the scope and application of international law governing the use of force and key challenges posed by the character and conduct of contemporary war.

Throughout the course, we will be drawing on legal texts, academic debates and case studies and to engage with current debates on the changing character of war and on the changing – and contested – landscape of the international law of war.

No previous knowledge of international law is assumed for those taking this module. 

*Please note that module information is indicative and may change from year to year.

Staff information

Not applicable

Teaching pattern

One-term course, 1 x 11 weeks

Module assessment - more information

All War Studies Online modules are 20-credit modules and will be assessed by:

  • 1 x 1500-word short essay
  • 1 x 3000-word long essay
  • In addition you will be assessed on participation within the discussions

Key information

Module code 7SSWM186

Credit level 7

Assessment coursework

Credit value 20 credits

Semester Full-year

Study abroad module No