is the essential point. We aren't here just to talk humanitarian aid. We need a democratic transition."
The release on the eve of the talks of thousands of photographs apparently showing prisoners tortured and killed by the government reinforced opposition demands that Assad must quit and face a war crimes trial. The president, who succeeded his father 14 years ago, insists he can win re-election and wants to talk about fighting "terrorism."
Assad has been protected by Russia, his main arms supplier, which dislikes Western attempts to overthrow incumbent leaders.
But Washington and Moscow share alarm at the spread of the violence that has already killed more than 130,000 Syrians. Having set aside their differences last year to co-sponsor the talks that are finally getting under way, Russia and the United States profess an urgent common goal of halting the bloodshed.
"It is hard to have expectations at the back of all this," said a source at the talks who has advised the opposition. "But Moscow and Washington are genuine on ending the conflict. They are sincere and this meeting is not for show."
Assad's representatives may highlight the threat to the West and its Arab allies from al Qaeda and other militants fighting his forces. But Western leaders say they fully back opposition demands that Assad step down, something they say was the conclusion of the U.N. conference in Geneva 18 months ago.
Russia endorsed that communique but has disagreed with Western powers which say that, by calling for a transitional government in Damascus, the meeting known as Geneva 1 made Assad's removal a condition for a peace settlement.
Neither side in Syria has either appeared able to complete a victory. Though much divides the rebels, who have been fighting among themselves, they are united in wanting Assad out. So reaching a settlement that satisfies both sides seems a distant prospect.
Discontent stretches back to the rule since 1970 of Assad's father, who took power in a military coup, but it boiled over in March 2011 as Syria's drought-hit economy struggled and the Arab Spring uprisings in Tunisia and Egypt inspired protests.
When those were crushed,