By Louis Charbonneau
UNITED NATIONS, June 28 (Reuters) - How deep is the divide separating Russia and the United States on Syria? A photo from the recent G8 summit in Northern Ireland says it all - two grim-faced leaders slouched in their chairs, Barack Obama biting his lip and Vladimir Putin staring at the floor.
The awkward photo opportunity, which went viral on the Internet, highlights the increasingly tense relationship between the former Cold War foes who find it difficult to agree on a series of high-profile issues, including Syria and a fugitive U.S. intelligence contractor whom Putin refuses to extradite.
Washington and Moscow have been trying since May to organize an international peace conference to bring an end to the violence. But hopes that such a conference will take place anytime soon - if at all - are fading quickly.
U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov originally announced that they would try to hold the conference, which is intended to bring rebels and representatives of Syrian President Bashar al-Assad's government to the negotiating table, by the end of May.
But the date keeps slipping. First it was bumped to June, then July. Earlier this week U.N.-Arab League peace mediator Lakhdar Brahimi, who held talks with senior U.S. and Russian officials in Geneva, ruled out a peace conference before August.
Diplomats at the United Nations in New York say it is unclear whether the peace conference will take place at all.
"It's not looking too good," a senior Western diplomat said.
The point of the conference was to revive a plan adopted last year in Geneva. At that time, Washington and Moscow agreed on the need for a transitional Syrian government, but left open the question of whether Assad could participate in the process.
The United States, like the Syrian rebels, says Assad and his family should play no role in a transitional government, though Russia says there should be no conditions on the talks.
Kerry and Lavrov will discuss Syria again next week on the sidelines of an Association of Southeast Asian Nations conference in Brunei, the United Nations said on Tuesday.
ASSAD WON'T HAND OVER POWER
There are other sticking points in discussions on how to make what U.N. diplomats have been calling "Geneva 2" take place at all - who will represent Assad's government and the Syrian opposition at the negotiating table. There is still no agreement on the lineup of potential negotiators. Then there is the issue of whether Assad's other key ally Iran should participate, as Russia wants but Western governments dislike.
Recently, Assad's forces have enjoyed some military successes. They recaptured two towns near the Lebanese border, while rebels complain about insufficient arms and ammunition.
This, diplomats say, makes both Assad's government and the opposition more reluctant to seek a compromise and diplomacy in Geneva - Assad because he thinks he can win the war militarily, and the opposition because it does not want to negotiate from a position of weakness and is holding out for more weapons.
Assad's foreign minister, Walid al-Moualem, told a news conference earlier this week that authorities were ready to form a broad-based government of national unity. But he made clear that they were not planning to give up control of Syria.
"We head to Geneva not to hand over power to another side," he said. "Whoever on the other side imagines this, I advise them not to go to Geneva."
Some diplomats say the ebbing hopes for a serious peace conference highlights the impotence of the United Nations and Brahimi, who for months has threatened to quit the post like his predecessor, former U.N. Secretary-General Kofi Annan.
Annan quit the job last year out of frustration at the way the dispute between Russia, Assad's main arms supplier, and the United States, which supports the rebels and recently announced it would begin providing them with arms, has left the Security Council in a state of paralysis on the Syrian issue.
Russia and China long ago ruled out sanctioning Syria and have vetoed three Western and Gulf Arab-backed resolutions condemning Assad's government for an increasingly sectarian war that the United Nations says has killed more than 90,000.
GRIM PROSPECTS FOR DIPLOMACY
Richard Gowan of New York University predicted that a collapse of Kerry's peace conference plan will increase pressure on Obama to send more and heavier weapons to the Syrian rebels.
"If the Geneva proposal fails, there will be pressure on the U.S. to move beyond its current offer of light weapons to the rebels, especially if Assad's forces score more victories," Gowan said.
"Kerry's bet on Geneva may backfire by demonstrating that diplomacy is really a lost cause, but perhaps Kerry, who has reportedly argued for air strikes, is fine with that," he said.
Washington's cautious move to begin arming moderate Syrian rebels - not Islamist militants who are increasingly present in the conflict - came after it said Assad's forces had crossed a "red line" by using chemical weapons.
The Syrian government denies the charge and says the rebels have used chemical arms. It also accuses Western and Gulf Arab governments of arming the opposition.
U.N. Secretary-General Ban Ki-moon, now in his second and final term, is increasingly worried that he may be remembered as the man who failed in Syria, U.N. diplomats told Reuters. He has even considered stepping in himself to try to broker a peace deal if Brahimi throws in the towel, the envoys added.
Outgoing U.S. Ambassador Susan Rice, who will soon take up the post of Obama's national security adviser, said earlier this week that the council's failure to take decisive action on Syria was a "moral and strategic disgrace."
"The repeated failure of the Security Council to unify on the crucial issue of Syria I think is a stain on this body and something that I will forever regret - even though I don't believe that outcome is the product of the action of the United States," Rice said.
British Ambassador Mark Lyall Grant echoed Rice's unusually strong words, which were clearly aimed at Russia and China. He also defended the United Nations against suggestions that the organization itself was somehow responsible for the Security Council's failure to act on Syria.
"People talk about it being a stain on the United Nations but you can't blame the United Nations," he said, adding that the responsibility lies with its member states.
"We have tried very hard over the last two years to secure some leverage for the Security Council in this crisis as it's unfolded," he said. "Unfortunately we've had three resolutions vetoed by Russia and China ... Events on the ground might have unfolded very differently had those resolutions been adopted."
A March 2011 council resolution authorized military intervention in Libya and gave a green light for NATO to mount an operation to protect civilians that led to Libyan leader Muammar Gaddafi's ouster and death at the hands of rebel forces.
No Western nations have called for something similar in Syria, and Russia has vowed to prevent a similar move in Syria.
There may be no swift end to the war. And even if the opposition were to prevail, it is unlikely to bring stability.
"The Syrian civil war is likely to go on for years," said Richard Haass, president of the Council on Foreign Relations.
"It is not just that it is proving harder and taking longer to oust the Assad regime than many expected," he told Reuters. "It is also that even if the regime were to be removed, what would follow would be a prolonged round of fighting among opposition forces who disagree on just about everything except their opposition to the current regime." (Reporting by Louis Charbonneau; Additional reporting by Dominic Evans in Beirut; Editing by Alistair Bell and Eric Beech)