Their contribution of tank-killing missiles for the rebels against Assad, and up to 100 strikes a week against Isis in north Syria, was trumped by Russia towards the end of 2015. Vladimir Putin's gift of direct air power for Assad, now providing up to 500 sorties a week against all enemies in Syria, appears to have turned the tide.
Although Assad may now be reversing many of his recent losses, it appears now that the 17 countries trying to solve this problem realise that the war has to stop as it has got out of control. The death toll is moving towards half a million, over a third civilians. Nearly half of the population of the country is displaced, with millions spilling over the borders, and a new generation of religious-inspired terrorist groups has been spawned in the chaos, seeking to kill the innocent, far and wide.
The first step in trying to solve this problem is the cessation of hostilities between the groups not classified as terrorists. A cessation of hostilities is not a ceasefire or a truce in which intermediaries get between the two sides to monitor violations. A cessation is the most basic good-faith requirement as a first step towards discussions about what peace may look like.
All of the difficult questions for that peace, be they questions about the future of Assad or whether Syria should be divided, are yet to be addressed. Yet, before the killing stops between those who are meant to negotiate, substantive peace talks cannot begin.
Few have high hopes that the cessation of hostilities will start, let alone hold. Even if the superpowers at the top table want the shooting to stop, it is far from certain that those doing the shooting want the same.
If the cessation does not take hold and meaningful peace talks do not follow, the problems are going to escalate in three areas.
First, if Assad gains the upper hand, expect up to three million refugees - three times the number of 2015 - to seek sanctuary in Europe from a vengeful victor.
Second, expect the forces of Isis and al-Nusra to grow in strength as anti-Assad fighters and supporters move their allegiances and the middle ground gets squeezed out of the war.
Third, Turkey and Saudi Arabia, neither of them willing to see Assad return to full power, may decide to engage directly in the conflict, creating a real threat to international security through their defence treaties that could force many other countries directly into the fray.
Even if they do not provide boots on the ground, either country may surreptitiously deliver the air-to-surface missiles the enemies of Assad require to stay in the fight by taking down the Russian planes.
Without peace, the prognosis in all areas is very bad. We can only start to turn this around if, on Friday, the guns fall silent and the sound of bombs exploding is replaced by the sound of trucks delivering aid.
It would be a small step, but the first step in a very long time, going in the correct direction.
• Alexander Gillespie is a professor of law at the University of Waikato.
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