Syria is embroiled in a civil war. The US could decide to help one side win; alternately, we could just stay out of it. Instead, we're taking a third route: purposely working to ensure that nobody wins.
The White House is no longer a big fan of the murderous dictator Bashar al Assad. But it's not a big fan of the various Islamist factions among the rebels fighting against Assad, either, because it perceives them to be strongly anti-American. One reasonable position to take in light of all this would be: we are simply not going to get involved in the Syrian civil war. Another defensible position would be: because we support the right of people to be free of dictators and to choose their own leaders, we will support the rebels, and if the rebels choose to eventually put Islamists in power, that is their democratic right, which we respect on principle.
Of course, US foreign policy does not operate on principles, except for the principle of the preservation of US interests. In Syria, it certainly does not operate with an eye towards saving the lives of as many Syrians as possible. Here is how the US has decided to reconcile the competing interests in Syria: by supporting the one faction that we find agreeable—but not enough for them to win. Greg Miller explains in the Washington Post:
The CIA’s mission, officials said, has been defined by the White House’s desire to seek a political settlement, a scenario that relies on an eventual stalemate among the warring factions rather than a clear victor. As a result, officials said, limits on the agency’s authorities enable it to provide enough support to help ensure that politically moderate, U.S.-supported militias don’t lose but not enough for them to win.
The US government is actively working to ensure that nobody can win in Syria. We have chosen a side to support, yes; and then we have made the conscious decision to help them just enough to keep them in the game, but not enough for them to prevail. We are, as a policy, encouraging the war to continue, and encouraging more fighting, in the hope that the long war will eventually bring all parties to the bargaining table. Long war with no winner is now the US policy of choice, in Syria.
The Syrians may not enjoy this strategy.