On Monday night, the US State Department announced
it would be "suspending its participation in bilateral channels with Russia" which had come about as part of an effort to end the Syrian Civil War.
This drastic move comes after weeks of growing frustration in Washington. "Everybody's patience with Russia has run out," White House Press Secretary Josh Earnest said Monday night. He added that Russia had made a "series of commitments without any indication they were committed to following them."
This frustration is easy to understand. The US placed a lot of faith in Russia, and Secretary John Kerry had invested a huge amount time and energy working with his Russian counterpart Sergei Lavrov, on the assumption that both he and the Kremlin were seeking an end to the fighting.
Though it may still be true that Russia would like to see an end to the conflict, what that outcome looks like and how it might be achieved is as open to question as ever. For some time, the US believed the Russians were open to a political solution in Syria for the simple reason that they were not obviously pursuing a military solution. It's now clear this was little more than wishful thinking.
Russia has time after time failed to restrain Bashar al-Assad. It is either unable to hold the Syrian leader to commitments he previously agreed to, or doesn't want to.
The ceasefire agreed last month
-- designed to stop fighting for long enough so that moderate Syrian rebels could disassociate themselves from terrorist groups, therefore allowing the Syrian government to focus on this enemy and creating the conditions for a political solution to ending the crisis -- was declared "at risk" by Russia after US airstrikes killed Syrian soldiers. Russia said the bombing was "frankly suspicious"; the US said it was accidental.
It fell then beyond rescue after a humanitarian aid convoy was bombed trying to enter Aleppo. The US said at the time that it held "the Russian government responsible for airstrikes in this airspace given their commitment under the cessation of hostilities was to ground air operations where humanitarian assistance was flowing."
The US now believes that Russia was actively assisting its Syrian partners in targeting civilian areas and civilian infrastructure.
It's clear that Russia has no intention of using its influence with Assad.
So what can the US do, other than put down its cards and walk away from the table, leaving Russia and Syria to find a solution on their own?
Can a solution be found?
The conflict will now have to play out and reach a point where countries like the US are once more inclined to start talking again.
Russia will no longer face the same level of international scrutiny; there is a reluctant acknowledgment that no one can influence its actions. Russia, it seems, is using the Syria conflict to throw its weight around and let the US know that it has a major rival on the global stage. What incentive does the Kremlin actually have to give up this trump card and bow to the White House?
But this doesn't mean that the war is about to accelerate to its conclusion.
Four months from now, it is entirely possible that Assad will have bolstered his position on the ground. To reclaim rebel-held areas, he will need to rely heavily on Shia militias from Iran and Iraq
. It may be that with an increased Shia presence in the country he is able to secure cities like Aleppo.
But that won't be straightforward. In absence of a proper peace deal, it's likely that the Saudis and other Gulf states will continue to fund rebel groups. The Saudis would ideally like Sunni boots on the ground, but will settle for backing Sunni rebels if the result is giving Assad a bloody nose.
In other words, the conflict may have lost a major player, but any peaceful end for Syria feels as far away as ever.