UN Law requires ideally for a head of state / government indited by The international Criminal Court to make a peace agreement with the other side and face trial rather than further attricities and to help humanitarian aid. For someone (say President Assad Junior) to be assassinated would only risk tit for tat civil war or the states further militarisation under a general. In that scenario said individual could be so minded to try and retake the Golan which could risk the use of battlefield WMDs which could pollute teh water table of Israel/ Palestine/ Lebanon/ Jordan and Syria itself rather than aid in talks for the disarmament of Nukes from the region.