The applicability of international humanitarian law (IHL) to United Nations (UN) forces has long generated discussion. When peacekeepers have become engaged in hostilities of such a nature as to trigger the application of IHL (either via acts in self-defence, or in the course of carrying out a mandate as authorised by the UN Security Council under Chapter VII of the Charter of the United Nations), questions have arisen as to whether they should be equally subject to the rules of IHL. Such questions arise as UN peacekeeping forces act on behalf of the international community and thus have a ‘just cause’, so to speak, to use force. Despite these questions, however, it now appears well settled that the distinction between jus ad bellum (the right to use force under public international law) and jus in bello (the law governing the conduct of hostilities) should be maintained, and that IHL applies in respect of UN peacekeeping operations whenever the conditions for its application are met. That said, questions regarding the conditions for the application of IHL, as well as its scope of application, continue to be relevant, particularly at a time when the Security Council is tasking UN operations with increasingly robust mandates.

The issuance by the International Court of Justice (ICJ) of its Advisory Opinion on the consequences of Israel's construction of the separation barrier in the Occupied Palestinian Territories (OPT) raises myriad legal questions worth addressing. This paper focuses on one of the key claims made by Israel and a number of other states since the request for an Advisory Opinion was brought before the Court: whether the involvement of the Court in the issue of the construction of the barrier constituted an obstacle to Israeli-Palestinian peace.