Aims
This course aims to:
- introduce you to the contemporary law governing the use of force in international relations and allow you to assess whether collective security works
- enable you to understand the (largely unsuccessful) attempts to limit the use of force prior to World War II
- describe the change that came from the adoption of the UN Charter
- look at the contemporary world and consider what (if any) impact banning the use of force and the changes in the rules governing how wars are fought has had on today’s conflicts
Content
Carl von Clausewitz stated that 'War is the continuation of politics by other means', offering a clear understanding of why world history is punctuated by wars of conquest. Wars create, divide and destroy empires, built walls, roads and bridges, dammed rivers, and changed the very essence of our natural world. Empire-by-conquest was a universal, global, phenomenon that punctuated the ages.
But if the use of force as state policy was largely unrestricted before the 1920s, societies globally have long limited the manner in which force can be used: refusal to take surrenders or attacking civilians has long been contrary to societal norms in civilisations around the world. In understanding the use of force in the round, we need to understand what the limits on the manner in which force is used.
In October 1945 human history changed profoundly with the adoption of the UN Charter which made aggressive war illegal, and in the process, sounded the end of the European territorial empires that had dominated much of the world from the 17th century onwards. Indeed, the UN’s membership increased from 51 in 1945 to 154 by 1980 directly as the result of the dissolution of the European empires.
However, if you were a visitor from Mars, you would be right to be confused: war seems to be used much as Clausewitz held. The University of Michigan’s Correlates of War lists 144 inter-state wars between 1945 and 2007, a total that has been consistently added to in the years since, suggesting that the Charter’s ban on the use of force is at best marginally relevant, or at worst has failed.
This course argues that despite these conflicts, collective security premised on the Charter’s ban on force remains the cornerstone of contemporary international relations, illustrated by the pseudo-legal arguments’ aggressors use to buttress their claims. This course examines the UN Charter and International Court of Justice jurisprudence and identifies where and how the law is developing.
Presentation of the course
This course will take the form of ten 90-minute lectures with slides and additional reading.
Course sessions
- What is the law?
This introductory lecture explains the different but complimentary sets of rules that govern the use of force. These comprise the law governing whether the use of force is legal (jus ad bellum) and whether the manner that hostilities were conducted is legal (jus in bello). This will allow us to categorise conflicts based as International Armed Conflicts, Non-International Armed Conflicts and mixed-status conflicts. As we will see, the status of a conflict is essential in determining what the applicable law is.
- Developing the law of war
We will chart the regulation of war from its earliest days through the Middle Ages to the First World War. We will see that there is a breadth of international practice and similar laws in very different cultural and historical contexts, coming together in the creation of the International Committee of the Red Cross (ICRC) under Henri Dunant, and the first attempts at arms control in the 19th century.
- The use of force before 1945
The use of force to settle interstate disputes has been the cornerstone of interstate relations since humans settled in the Fertile Crescent. Conquest, subjugation, assimilation, rebellion, conquest became the norm through to the creation of the early modern European empires and the First World War. Limitations on force came to rely on deterrence by alliances offering collective security guarantees. Why did these (largely well-meaning) attempts fail?
- The use of force in the UN Charter
Drawing on the lessons from the failure of the League of Nations to prevent World War II, we will look at how the UN Charter was negotiated and how substantive law wrought was up-ended by the Entry Into Force of the UN Charter in October 1945. We will consider the trade-offs delegates faced in San Francisco, and how those compromises, notably around the Security Council’s remit and the role of the veto, continue to affect international relations.
- Postwar jus in bello: The 1949 Geneva Conventions, the Genocide Convention, the UDHR and the Additional Protocols (1979, 2005)
World War II’s crimes saw the law evolve in important ways, with the passage of the four Geneva Conventions in 1949, the Genocide Convention in 1951 and the Additional Protocols to the Geneva Conventions which united Hauge Law and Geneva Law in 1979. Buttressed by the Universal Declaration on Human Rights and the plethora of Human Rights instruments, this lecture will outline contemporary jus in bello.
- Use of force in the UN Charter Era
Sadly, the prohibition on the use of force did not stop wars in the years after 1945: between 1945 and 2000, more than 41 million people died in conflicts. In the 25 years since, we have seen major wars in Congo/Great Lakes, Afghanistan, Iraq, Syria, Yemen, Ukraine, Israel/Palestine and insurgencies around the world. Through considering state practice, the judgements of the International Court of Justice and evolving norms, we will examine how the law on the use of force has developed since 1945, and what today’s law is.
- Defining Aggression and the Responsibility to Protect (R2P)
The key blocker to the creation of an ICJ Criminal Chamber in the 1950s was an inability for the international community to agree on a definition of aggression. We will trace how this was successively dealt with, and how it is now (imperfectly) prosecutable at the ICC as an international crime. In the second half of this lecture, we will look at what happens when the Security Council is confronted by atrocity and is unable or unwilling to come to a consensus on how to act.
- Ending Impunity: Enforcement of Jus in bello / Jus ad bellum
Legislation has several roles, including shaping international norms. But no role is more important than allowing for enforcement through prosecution. This lecture begins with the International Military Tribunals (IMT) at Nuremburg and Tokyo after World War II, and then moves to the International Criminal Tribunals for Rwanda and Former Yugoslavia (ICTR/ICTY), before looking at today’s International Criminal Court (ICC).
- Case Study: Israel-Palestine: before and after 7 October 2023
The conflict in Israel and the Occupied Palestinian Territories has resulted in a major contemporary war and testing all of the rules we have discussed in lectures 1 – 8. This lecture will bring these lessons together and draw some conclusions on the ability of the law to regulate conflict.
- Post–Cold War collective security: success or failure?
Concluding the course, we will assess whether collective security and international law in the Cold War’s aftermath has succeeded or failed. What does the future hold?
Learning outcomes
You are expected to gain from this series of classroom sessions a greater understanding of the subject and of the core issues and arguments central to the course.
The learning outcomes for this course are:
- to become familiar with contemporary international law governing the use of force (both jus in bello and jus ad bellum).
- to assess whether a State’s use of force is legal or illegal, and if force is used, whether it is used legally or illegally.
- to understand the current debate on the use of force (eg, by non-state actors, cyber-attacks) and their integration into the legal order
Required reading
You will need to have one of
*Crawford, E, Pert, A, International Humanitarian Law (Cambridge: Cambridge University Press 2024, 3rd Ed) ISBN: 9781009326728
(This is a very readable introduction to the subject.)
Or
*Solis, G D,The Law of Armed Conflict: International Humanitarian Law in War, (Cambridge, Cambridge University Press 2021, 3rd Ed) ISBN: 9781108831635
(Solis’s book is more detailed study than Crawford’s and would be my recommendation if you’re interested in taking the subject further, though it is more demanding of the reader.)
And one of
*Gray, Christine D, International Law and the Use of Force (Oxford: Oxford University Press 2018 4th Ed) ISBN: 9780198808428, Chapters: 1, 4, 6, 7
*Henderson, Christine, The Use of Force and International Law (Cambridge: Cambridge University Press 2023, 2nd Ed) ISBN: 9781108831017
Please make sure that you have the latest edition of each work – the case law is evolving, and it is important to have the most recent one.
Treaties
Please familiarise yourself with the UN Charter.
*UN Charter, https://www.un.org/en/about-us/un-charter/full-text
*R2P – see paras 138 and 139 of the 2005 World Summit Conclusions: https://www.globalr2p.org/resources/2005-world-summit-outcome-a-60-l-1/
United Nations General Assembly (UNGA) 2005 World Summit Outcome (2005) UN Doc A/Res/60/1 paragraphs 138–39, available from: A/RES/60/1 2005 World Summit Outcome (un.org)
1949 Geneva Conventions
1951 Genocide Convention
1977 Additional Protocols to the Geneva Conventions 1949
‘Yale Club roundtable: a special tribunal for the crime of aggression recommended
by the UN General Assembly’ https://www.justsecurity.org/wp-content/uploads/2022/09/UNSC-Letter-12-August-2022.pdf
Uniting for Peace Resolution (UNGA Res 377A/B/C (V)): see Christian Tomuschat’s article: https://legal.un.org/avl/pdf/ha/ufp/ufp_e.pdf and the Resolution itself: https://www.un.org/en/sc/repertoire/otherdocs/GAres377A(v).pdf
Kress, Claus, ‘On the Principle of Non-Use of Force in Current International Law’,
https://www.justsecurity.org/66372/on-the-principle-of-non-use-of-force-in-current-international-law/ (30 September 2019)
ICJ Cases
‘Armed Activities on the Territory of the Congo’ (Democratic Republic of the Congo v Uganda), Judgment, [2005] ICJ Rep 168: 116-20051219-JUD-01-00-EN.pdf (icj-cij.org)
‘Military and Paramilitary Activities in and against Nicaragua’ (Nicaragua v. United States of America), Merits, Judgment, [1986] ICJ Reports 14: 070-19841126-JUD-01-00-EN.pdf (icj-cij.org)
ICJ Advisory Opinions
Advisory Opinion Concerning Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, 9 July 2004 (https://www.icj-cij.org/sites/default/files/case-related/131/131-20040709-ADV-01-00-EN.pdf)
Legal Consequences arising from the Policies and Practices of Israel in the Occupied Palestinian Territory, including East Jerusalem, 19 July 2024 (https://www.icj-cij.org/sites/default/files/case-related/186/186-20240719-adv-01-00-en.pdf)
