On 18 December 2015, the UN Security Council, having overcome the gridlock on Syria that had persisted since October 2011,Russia and China veto draft Security Council resolution on Syria UN website, 4 October 2011. unanimously passed Resolution 2254 (2015), endorsing the ISSG's transitional plan that set out a timetable for formal talks and a unity government within six months; the resolution put UN special envoy Staffan de Mistura in charge of organising Syria talks. However, the major powers remained divided on who should represent the Syrian opposition; no mention was made of the future role of Syrian President Bashar Assad.
