Limits of military force

The use of military force is characterized by the tension between what is possible and what is necessary. Nuclear arsenals, the (self-)control of unmanned drones, cyberattacks, humanitarian interventions, the War on Terror, or the torture of prisoners—all of these raise the question of where the line between military necessity and possibility should be drawn, and when it is crossed. Which military options are ultimately realized does not depend solely on strategic, tactical, or operational considerations, but is also defined by international humanitarian law and international criminal law. Together with human rights, these frameworks establish both the protection of non-combatants and the treatment of combatants, thereby providing a benchmark for assessing what is militarily necessary. At the same time, international law is not only codified in positive legal instruments, but also rests on customary law. The Responsibility to Protect (R2P) is among the more recent normative expectations in the international legal context. Although this principle has not yet been fully codified in law, it nevertheless served as a justification for the use of military force in Libya.

Contemporary international humanitarian law and international criminal law emerged out of the rupture of the Second World War and the founding of the United Nations. The Holocaust, Wehrmacht crimes, the use of weapons of mass destruction, and the mass mobilization of populations expanded warfare to a seemingly boundless extent. Yet the law of war had already been codified by European states in the early 20th century. During the Hague Peace Conferences of 1899 and 1907, Western states negotiated the Hague Regulations, while the first Geneva Convention of 1864 had already established protections for the wounded and their care by the International Committee of the Red Cross. During the U.S. Civil War (1861–1865), the Lieber Code regulated the conduct of U.S. soldiers well into the 20th century and influenced various international agreements. The codified law of war was based on natural law traditions shaped by ethical and moral notions of honor and valor as well as theological and Christian precepts. Theories of warfare, especially Carl von Clausewitz’s (1780–1831) On War (published posthumously in 1832), further framed questions of military necessity in terms of strategic and tactical success. Hugo Grotius (1583–1645), reflecting on the Dutch War of Independence against Spain (1568–1648), developed classical international law and discussed the bellum iustum in relation to the permissibility of killing civilians in war. The concept of bellum iustum itself reaches further back, to the writings of Augustine of Hippo (354–430). The boundaries of military force—and perceptions of their transgression—thus originated in ethical, moral, and theological traditions and gradually developed into the law of war and modern international humanitarian law. Following the Second World War, the Nuremberg Trials marked the first criminal proceedings on this basis. At the end of the 1990s, the Rome Statute established international criminal law in treaty form.

This continuous transformation of legally drawn boundaries and their violations through military force is at the core of the ICWC’s research focus. The Center addresses these issues through academic conferences and scholarly activities on topics such as the use of military force in the name of human rights, the Responsibility to Protect (R2P), international humanitarian law, and the historical development of legal and ethical boundaries in armed conflict.