Analysis As the UN envoy, Kofi Annan is representing a UN that has not supported the Arab League plan in the Security Council.
Selling Syria peace deal a long shot for Kofi Annan
It is up to the former secretary general of the United Nations to reconcile disparate international views of the conflict into a coherent message.
"We should pool our efforts and work together," Mr Annan said last week. "When the international community speaks with one voice, that voice is powerful."
But at the heart of the international divide are divergent positions on Syria held by Gulf Arab nations - who want the Syrian president, Bashar Al Assad, out - and Russia, who is defending him. It is a split that Mr Annan has begun to grapple with as he made the diplomatic rounds at UN headquarters in New York at the end of last week.
The division is inherent in the joint title Mr Annan has assumed as envoy of both the Arab League and the United Nations.
As the League's messenger, he can be expected to try to sell an Arab League plan to Mr Al Assad, who has already rejected it.
The plan calls for Mr Al Assad to delegate authority to a vice president while a national unity government is formed leading to elections.
As the UN envoy, Mr Annan is representing a UN that has not supported the Arab League plan in the Security Council because of Russian and Chinese opposition. It was endorsed only in a non-binding resolution by the General Assembly, which created Mr Annan's post.
A Security Council diplomat said Mr Annan would likely avoid pushing the Arab League plan on Damascus, at least at the outset. This has led Russia so far to support his mission, he said.
"He wants to get a political solution to end the violence," the diplomat said. "He's got to build up trust with Assad and if he says I'm here to implement the Arab League plan . that's not the way to get it. He's not going to go around publicly saying I want Assad out. That's diplomacy 101."
Speaking to reporters last week, Mr Annan acknowledged the international divisions by tacitly chiding both Russia and some Gulf countries.
"If we are going to succeed, it is extremely important that we all accept there should be one process of mediation," Mr Annan said. "The one both the UN and the Arab League has asked me to lead."
This appeared to be a veiled reference to a separate attempt by Russia to bring the parties to Moscow to negotiate a settlement - an attempt rejected by the opposition.
Mr Annan made a more direct criticism of Saudi Arabia and Qatar, in particular, for openly calling for the opposition to be armed.
Diplomats claim privately that both countries are already sending weapons into Syria.
"I know there are people who have other ideas, that dialogue may not be the way to go and one should use other means," Mr Annan said. "But I think, for the sake of the people, for the sake of the Syrian people who are caught in the middle, a peaceful solution, through dialogue and a speedy one is a way to go."
It remains to be seen what alternatives Mr Annan has to convince Mr Al Assad that the best deal is to accept the Arab League plan, which envisions dialogue without the president. It is also not clear whether Mr Annan can convince the opposition to negotiate.
"Kofi Annan is going to do the Arab agenda - the Arab League plan," said Ali Al Ahmed, the director of the Institute for Gulf Affairs in Washington. "They couldn't get it through the UN [Security Council], so they are using a former secretary general who is going to build up momentum in terms of condemning Syria internationally."
Ray Takeyh, an analyst at the Council on Foreign Relations, said he believes that even with a unified international community, Mr Annan cannot now bring the conflict to an end.
"The UN has had a limited role and the Assad regime is determined to survive at all costs," he said.
"So it is an impossible task to begin with," said Mr Takeyh. "UN mediation can work best when everyone wants a way out. "
That might happen if the violence persists, creating an "appetite for a regional or international settlement".
But for the moment, he said: "This is a civil war and somebody will lose and somebody will win."