The threat or use of tactical nuclear weapons through the lens of sustainable development

In recent decades, tactical (or “non-strategic”) nuclear weapons have gained relevance in the nuclear postures of nuclear-armed states. The legality of their threat or use under international law, however, remains unclear, particularly because the International Court of Justice declined to elaborate on tactical nuclear weapons in its 1996 Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons. While the Court expressly grounded its reasoning in the “current state of international law” at the time, the international legal framework has evolved over the last three decades in the field of environmental protection and under the influence of sustainable development. The present contribution assesses the influence that these developments have had on the legality of the threat and use of nuclear weapons and examines whether the International Court of Justice’s analysis in the Nuclear Weapons Opinion retains its force today with respect to the conceivability of “clean” uses of tactical nuclear weapons.