The crisis in Syria is clearly at a tipping point, but despite the events on the ground and the reassessments made by foreign powers, the end game may still be some ways off.
The road to a peaceful Syria still runs through Moscow
Twenty-one months after the start of the revolt in Syria, just about everyone seems to agree that the conflict has reached a tipping point. The regime of Bashar Al Assad has lost so much ground that it cannot win the war by military force. The economy is teetering, with fuel in short supply. And there is a risk that the southern part of the country could soon be deprived of electricity. In six months, predictions say, the country will be bankrupt.
The growing humanitarian emergency, with hunger in the rebel-controlled north and 2,000 to 3,000 people leaving the country a day, means that the world can no longer shrug its shoulders.
Meanwhile the regime has taken ever-more-desperate actions, such as bombing the Yarmouk Palestinian refugee camp, a potential entry point for rebels into the capital. This unnecessary act threatens to turn the Palestinians from neutrals into enemies of the regime, and is spurring a Palestinian exodus with unpredictable consequences for Lebanon and Jordan.
Among the outside powers, the Russians, traditional supporters of the Assad dynasty, have let slip that they do not see much future for their ally and are sending a naval squadron to the Mediterranean to evacuate their nationals from Syria. This evacuation, although justified by the security concerns, has been delayed for months on the grounds that it will be seen as a vote of no confidence in the Syrian military.
The western powers have flocked to recognise the opposition Syrian National Coalition as the legitimate government of the country, even though its credibility is unproven. There is increasing talk of military intervention - not necessarily boots on the ground, but supplies of equipment and enforcement of no-fly zones and humanitarian corridors. Much of this talk seems designed to rouse Washington to action.
But Washington, keen to avoid another Middle East entanglement, has set the bar for intervention high: only if the Assad regime uses chemical weapons against the opposition, or loses control of them and allows them to fall into the hands of Hizbollah in Lebanon or the international brigades of jihadis.
The justification for western governments to step into the open with their support for the opposition is supposedly to influence a future Syria by supporting more secular elements of the opposition against the better-trained, and often better- supplied, extremists.
Not surprisingly there is a lot of concern in western capitals. Will Syria produce a second Afghanistan, where support for the mujahideen led to the creation of a global cadre of seasoned fighters dedicated to the downfall of America? Or will the result be mission creep, whereby western troops set foot in Syria, reviving memories of the Mandate period of the 1920s and 1930s or, more recently, the invasion of Iraq?
In Britain, members of parliament's foreign affairs select committee have written to William Hague, the foreign secretary, to question the "value, legitimacy and legality" of intervention in Syria.
Yet despite the events on the ground and the reassessments made by foreign powers, we do not seem to be at the end game. Just as the regime cannot win the war, so the opposition still lacks the firepower to take Damascus. For all the talk of tipping points, there is no reason why Mr Al Assad should not be in his presidential palace nine months from now. In Lebanon, the civil war lasted 15 years - and no one won: peace came when they lost the will to keep fighting.
There are other reasons why no imminent conclusion can be guaranteed. Clips on YouTube of army officers being summarily executed when they surrender have put paid to any idea that defecting units will be treated honourably. For the officers - 80 per cent of whom are said to be members of the Alawite sect that makes up only 12 per cent of the population - this war is a zero-sum game. If they are not in control, they feel, they are going to be slaughtered. For the most hard-line of the rebels, death is indeed the appropriate sentence for servants of a regime that imposed the death penalty for membership of the Muslim Brotherhood.
What can be done to prevent Syria from becoming a 15-year conflict? At the risk of stating the obvious, the key lies with Russia and Iran, the Syrian regime's backers. Russia has two choices: as Vladimir Putin, the Russian president, sees western powers getting more deeply involved, he might relish playing the spoiler, and watching as yet another plan goes sour.
But that would be shortsighted. Russia's ties with Syria are deep, through education, the military and intermarriage. Its interest is to retain Syria as a sovereign state and to prevent it from becoming a haven for extremists whose influence could stretch to Chechnya on Russia's southern border. Russia's interest in a quick change of power in Damascus is growing.
Iran is in a different position. Despite the 30-year alliance between Tehran and Damascus, the two countries are not natural partners and relations have always been rocky. When Iraq was led by Saddam Hussein, it was vital for Iran to have Syria as an ally. But Iran's key interest has always been to ensure that Iraq is not strong enough to be a military threat.
Happily for the Iranians, the Americans have achieved that goal for them by invading and toppling Saddam Hussein. Iran is now in a position to guide Baghdad and, if necessary, keep the country weak and divided. The importance of Syria has declined to that of a supply route and hinterland for Hizbollah. That, however, does not mean that Iran would necessarily be a willing party to any peace deal. The mullahs would surely want to know if US policy towards them continues to be what it was towards Saddam Hussein: eternal sanctions until regime change.
Turkey is clearly the best placed to explore how to turn these considerations into a peace plan. Success is hardly assured, but the alternative is months or years of war.
On Twitter: @aphilps