Course description
The justification of war and securing of peace have been major subjects for legal thought and practical regulation since the very beginnings of recorded history. For most of this vast period, and in most civilizations, the conceptualization and organization of restoring and ensuring peace have been premised on the legal conception of war. As long as war was considered, as it has been for over two millennia in the European tradition, as an instrument for the pursuance of rights, peace could not be construed as legally unbreakable. This approach to war also informed the rules about waging war, which dictate the behavior of belligerents and the level of protection of both combatants and non-combatants during war. As such, concerns about humanity have generally taken second place, not only in practice but also in the theoretical construction of the law, throughout the ages.

The 20th century has been marked by a veritable revolution in international law with regard to the laws of war- and peace-making. Between the Covenant of the League of Nations and the Charter of the United Nations, the right to war was first restricted and then overturned by a general prohibition for states to resort to war or to lesser forms of use of force. This revolution was largely concomitant to the rise of humanitarian concerns, which led to the emergence of international humanitarian law. While this was meant to constitute a radical break with the past, both in state practice and legal doctrine, old traditions, ideas and doctrines persist. This has thrown the law about war and peace, arguably the most significant part of the politico-legal constitution of the world into disarray. The unclarity has been exacerbated by the rise of internal armed conflicts and the ‘War on Terror’, leaving the institutions and proponents of a world order and international law badly armed to provide peace and security today. In this context, concerns about international humanitarian law and human rights law have sometimes become double-edged, in that more human forms of warfare serve as platforms to argue the perpetualization of limited forms of ‘warfare’.

This course introduces students to one of the core, historical subjects of the normative regulation and organization of international order. It discusses the historical development of the laws and institutions for making war and peace from Antiquity to the present war in Ukraine. It integrates theoretical reflections by legal and political thinkers with the practices of rulers, governments and diplomats for the justification of war and the making of pace.

The course covers the Ancient Near East, classical Greece and Rome before moving to the Christian and Islamic world in the Middle Ages. The course gives ample attention to the crucial developments in the Early Modern Age, both with regard to the development of the sovereign state and European colonization and empire-building outside Europa. It then turns to modern international law and imperialism in the nineteenth century. The Covenant and Charter eras are discussed in depth. The course ends with several recent case studies: the Six Days War, the three Persian Gulf wars (1980, 1991, 2003), the wars over Namibia and Angola leading to peace in 1990, the War on Terror and the invasion of Afghanistan (2001), the Israeli invasion of Lebanon (2006) and the war over Ukraine (2014-present).

Learning outcomes
At the end of the course, students have
- A general understanding of the historical development of major doctrines and institutions with regard to the justification of war, the waging of war and the making of peace.
- An understanding of the current international law and order with regard to these subjects.
- An insight into the place of legal norms and institutions in geopolitical decision-making about war and peace.
- An insight into the current security challenges for the global order that partially arise from the disorganization of the international legal system.

Teaching and evaluation method
Students are expected to read the literature for the week in advance of the classes and to make note of the subjects they want to see discussed with more depth in class. The lectures make ample use of historical texts, projected on screen, which are analyzed in order to discover and unearth the most salient points.

The evaluation consists of three parts:
- Student participation (activity and relevance): 10 % before the midterm, 10 % after the midterm
- Paper (2.500-4.000 words): students choose a war or a peace treaty and analyze it with regard to the normative framework applied in their source. Students give a brief 10 minutes presentation of the key finds of their paper during the final 4 hours of class (40 % of the grade, divided 30/10). Students can turn in their papers during weeks 9-11 of classes and receive feedback before exam week.
- Open book, open-question written exam with 4 short essay questions (40 % of the grade).

Bibliography
- Oona A. Hathaway and Scott Shapiro, The Internationalists and their Plan to Outlaw War (Allen Lane 2017), chapter 13.
- Majid Khadduri, War and Peace in the Law of Islam (John Hopkins UP 1955), sections iv, v, vi, xii and xviii.
- Randall Lesaffer, ‘Peace Treaties and the Formation of International Law’ in Bardo Fassbender and Anne Peters (eds.), The Oxford Handbook of the History of International Law (Oxford, 2012) 71-94.
- Randall Lesaffer, ‘Peace through Law: the Hague Peace Conferences and the rise of the ius contra bellum’, in Maartje Abbenhuis, Christopher Ernest Barber and Annalise R. Higgins (eds.), War, Peace and International Order? The Legacies of the Hague Conferences of 1899 and 1907 (Routledge Studies in Modern History; London and New York: Routledge 2017) 31-51.
- Randall Lesaffer, ‘Grotius on Reprisal’, Grotiana New Series, 41 (2020) 330-348.
- Randall Lesaffer, ‘Aggression before Versailles’, European Journal of International Law, 29 (2018) 773-808.
- Samuel Moyn, Humane. How the United States Abandoned Peace and Reinvented War (Farrar, Straus and Giroux 2021), Chapter 7.
- Stephen C. Neff, War and the Law of Nations. A General History (Cambridge UP 2005), chapters 1, 2, 3, 6, 8, 9 and 10.

Note: one of these chapters (‘Peace treaties and the formation of international law’) may be replaced by two newer chapters on peace-making from volume 6 of The Cambridge History of International Law (due for publication 2024-5).

Last updated: January 29, 2025