geneva syria opposition must accept six-and-a-half year war president bashar al-assad u.n. peace talk mediator staffan de mistura say wednesday de mistura suggest war almost many countries get involve principally defeat islamic state syria national ceasefire follow soon main rebel-held area city idlib would freeze opposition message clear plan win war facts prove case time win peace tell reporters ask imply assad say pro-government force advance militarily nobody could actually claim war victory sustainable political long-term solution otherwise instead war god forbid may see plenty low intensity guerrilla conflict go next 10 years see reconstruction sad outcome win war de mistura plan join ceasefire talk kazakh capital astana next week say help resolve fate idlib city million rebel designate terrorists unite nations gain influence confident ... non-conflictual solution let say new aleppo want avoid cost learn past say refer great battle humanitarian crisis war take place idlib may become freeze way order avoid become major tragic end conflict meanwhile islamic state face imminent defeat two main zone influence city raqqa around city deir al-zor fact deir al-zor almost liberate fact far concern liberate matter hours raqqa fall would follow within days weeks lead moment truth round negotiations october since early 2016 de mistura oversee tortuous series peace talk geneva make almost visible progress say next round could see accelerate pragmatic approach issue government liberation deir al-zor raqqa ready prepare genuinely negotiate simply announce victory know know announce sustainable without political process opposition able unify realistic enough realize win war syrian opposition must accept war u.n