Is Syria's 'truce' worth the paper it's printed on?
World powers have agreed to seek a "cessation of hostilities" in Syria. With many competing interests at work, however, what are the chances of success?
Aid convoys are in position on the country's borders; officials are thrashing out the details.
Jan Egeland, the head of the Norwegian Refugee Council, who is in charge of trying to deliver aid into Syria, has declared: "This could be the breakthrough we have been waiting for."
But other diplomats warn it might not be worth the paper it was written on. So what does this agreement amount to?
On the one hand, it does not sound too promising. Firstly, it is not intended to be a fully-fledged ceasefire but a pause in the fighting to let humanitarian supplies into besieged areas.
Secondly, it is only an expression of intent, not a roadmap for implementation. And plenty of past hoped-for truces in Syria have fallen by the wayside.
Thirdly, securing access for aid-convoys means agreeing clear terms for a pause in the fighting. This will require "buy-in" from multiple fighting groups, but already there are sharp differences over what any truce would cover and which groups constitute the so called terrorists who can still be attacked.
On the other hand, any plan for delivering aid is better than nothing, and a series of modest truces might be easier to agree upon than a more ambitious plan.
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Even if there is disagreement over the Russian bombardment of Aleppo, it is possible that a deal to let aid convoys into other parts of Syria could be reached. And there is always the hope that a plan to deliver aid might provide the first step towards getting peace talks back on track.
So is the glass half full? Or half empty? One way of trying to understand this complex puzzle is to disentangle the basic needs and intentions of different sides.
US and Europe
The United States, Europeans, and their allies find themselves caught in the middle. They want to intensify their air campaign against what they see as the main threat in the region, the so-called Islamic State (IS). Ousting IS from its strongholds of Raqqa in Syria and Mosul in Northern Iraq requires co-operation from the Russians, so falling out with Russia at this point is not seen as helpful at all.
At the same time, the West needs to ease the humanitarian devastation caused by the conflict, and that means President Assad and his Russian and Iranian backers to stop their bombardments. It also means quietly putting pressure on the representatives of moderate opposition forces to stop fighting and agree to return to peace talks.
An added complication is what drives Saudi Arabia and other Sunni Gulf States. Their focus in Syria is above all the balance of regional power - they may be alarmed by the reach of IS jihadism but just as important to them is to stop Mr Assad regaining control, for fear Syria might become a strategic foothold for the main Shia power in the Middle East, Iran.
When it comes to Turkey, President Recep Tayyip Erdogan's concerns are even more complex. He too does not want to see President Assad re-established as a viable leader of Syria. Nor does he want a deepening conflict to force him to take in yet more Syrian refugees, especially if new arrivals might include displaced rebel fighters.
But his added preoccupation - or some would say obsession - is what he claims is a mounting threat to Turkey's security from the Kurds. This is no longer for him just about the PKK Kurds inside Turkey, but also the Syrian Kurds with whom they are allied, and who have been quietly using the shifting battlefield in northern Syria to assert control over more territory along the border.
Perhaps the most important players in this conflict at the moment are President Assad and his powerful foreign backers. And of these, the Russians hold the key.
It is no secret that Moscow wants to redraw the Syrian map in Mr Assad's favour. Russia seeks to give him back a rump state that makes him a meaningful player again, and so Russian planes are crushing rebel forces around Aleppo. Removing the moderate opposition in Syria would strengthen Mr Assad's bargaining position in any renewed peace talks in Geneva by making him the only viable alternative to the IS threat.
This, presumably, is why the Russians initially did not want any truce to start until 1 March, giving them a clear three weeks to achieve their military objectives in Syria. So if now we find that talks over how to manage a truce take longer than expected, and Russia's fierce bombardment of opposition strongholds continues apace, it will be no surprise.
But in the end, it is probably quite likely that President Putin and his government will seek to co-operate in peace talks. Russia does not want to bear responsibility for the breakdown of any peace initiative, it wants to be able to claim to the high ground.
Also, the Russians have two practical reasons for keeping the door to diplomacy open, even if they are not ready to ground their warplanes.
In the first place, Russia's military operation in Syria was always intended to be time limited. Russia cannot afford to be drawn into a costly quagmire when the country is under pressure from the collapse in the value of the rouble and the drop in oil prices.
Secondly, Russia has for some time been eyeing the possibility of getting Western sanctions against it lifted. The EU is next due to review sanctions against Russia in July, just enough time for a short sharp military campaign to prop up President Assad's regime and then join in the peace talks. Maybe then the West will be persuaded that Moscow is a partner to work with rather than against in the fight against IS.
That, it seems, could be President Putin's plan. Whether the mesh of conflicting interests and antagonisms in and around in Syria will allow it to unfold as he might hope is another matter.