The United States and Russia have agreed to promote a ceasefire in Syria and allow critical humanitarian aid to reach affected cities and towns.  They also agreed to a joint targeting of the Islamic State and other Islamist militias.

This is the second ceasefire attempted this year.  In February, the two sides reached a similar agreement only to see it fall apart in days. 

Reuters:

"This all creates the necessary conditions for resumption of the political process, which has been stalling for a long time," Lavrov told a news conference.

The deal followed talks that stretched late into Friday night and several failed attempts to hammer out a deal over the past two weeks. The announcement on Friday was delayed as Kerry and U.S. negotiators consulted with officials in Washington.

"The Obama administration, the United States, is going the extra mile here because we believe that Russia, and my colleague (Lavrov), have the ability to press the Assad regime to stop this conflict and to come to the table and make peace," he said.

Previous efforts to forge agreements to stop the fighting and deliver humanitarian aid to besieged communities in Syria have crumbled within weeks, with the United States accusing Assad's forces of attacking opposition groups and civilians.

Kerry said the "bedrock" of the new deal was an agreement that the Syrian government would not fly combat missions in an agreed area on the pretext of hunting fighters from the banned Nusra Front, an al-Qaeda affiliate in Syria.

"That should put an end to the barrel bombs, and an end to the indiscriminate bombing, and it has the potential to change the nature of the conflict."

Under the agreement, Russian-backed government forces and opposition groups, supported by the United States and Gulf States, would halt fighting for a while as a confidence building measure. During this time, opposition fighters will have the chance to separate from militant groups in areas, such as Aleppo, where they have become intermingled.

If the truce holds from Monday, Russia and the United States will begin seven days of preparatory work to set up a "joint implementation center", where they will share information to delineate territory controlled by Nusra and opposition groups.

Both warring sides would pull back from the strategic Castello Road in Aleppo to create a demilitarized zone, while opposition and government groups would both have to provide safe and unhindered access via Ramouseh in the south of the city.

"We must go after these terrorists," Kerry said. "Not indiscriminately, but in a strategic, precise and judicious manner so they cannot continue to use the regime's indiscriminate bombing to rally people to their hateful crimes."

Kerry's words are pathetic.  And terribly naive.  What are the chances that President Assad will break off his nearly successful seige of Aleppo to please the United States?  Assad, the Russians, and Hezb'allah are on the verge of a spectacular victory.  Putin isn't going to try very hard to convince Assad to obey the ceasefire.

And the rebels?  They are fighting tooth and nail to hang on to Aleppo, perhaps the most important symbol of the rebellion.  The fact that they are fighting with al-Qaeda and other terrorist groups is out of necessity, and the notion that they would voluntarily separate and weaken their defenses is absurd.

The deal's documents will remain secret.  The reason for that is clear: the U.S. gave away the store to get Russia to go along.

Apparently, as part of the joint targeting of terrorists, we are going to reveal to Russia where U.S.-backed rebel forces are located.  For obvious reasons, the Pentagon is livid about this:

Pentagon and U.S. intelligence officials have spoken out against the idea of closer military cooperation with Russia, in particular the sharing of locations of opposition groups that have fought to topple Assad.

U.S. Defense Secretary Ash Carter, who only days ago delivered a forceful speech in England criticizing Russia, has long been skeptical of Moscow's intentions in Syria.

The Pentagon said in a statement it would carefully monitor the "preliminary understanding" agreed on Friday and cautioned the Assad regime and its backer, Russia, to stick to deal requirements.

"Those commitments must be fully met before any potential military cooperation can occur," Pentagon spokesman Peter Cook said. "We will be watching closely the implementation of this understanding in the days ahead."

I have zero confidence that any sort of ceasefire will last beyond a couple of days.  The violence will subside temporarily, but neither side has much motivation to quit fighting.  And as far as the joint targeting of terrorists, Putin will find a way to define "terrorist" in such a way that U.S.-backed rebels are bombed.

A failure all around compounded by betrayal.  That will be Obama's Syrian legacy.