June 14, 2013

PRESIDENT OBAMA has at last decided to deliver military support to Syria’s rebels, though the quantity and quality of any U.S. arms deliveries remain to be seen. It’s a move that, if made 18 months ago, might have decisively tilted the civil war against the regime of Bashar al-Assad and prevented the emergence of the extremist forces linked with al-Qaeda that are now active around the country. As it is, the action may be too small and come too late to achieve Mr. Obama’s stated goal of removing Mr. Assad from power.

The president’s hand was forced in part by strong evidence that the Assad regime had crossed a U.S. “red line” by using deadly sarin gas aganst rebels and civilians on multiple occasions; the White House’s announcement that chemical weapons had been used came months after Britain and France reached that conclusion. But Mr. Obama was also responding to desperate pleas from Gen. Salim Idriss, the commander of the rebel force that the United States says it supports. In a phone call to a senior State Department official and in a message to Washington, the general warned of preparations by the regime to mount a new offensive in Syria’s largest city, Aleppo, aimed at driving the rebels from districts they control.

Whether the United States and its allies can help prevent what could be a disastrous reverse to the anti-Assad cause will depend on how quickly arms supplies are delivered and whether they include the materiel Gen. Idriss says he most needs: not just ammunition for rifles and machine guns but also antitank rockets and antiaircraft systems. But merely preventing opposition-held districts in Aleppo from being overrun will not achieve U.S. aims in Syria. Administration officials appear to hope that small-scale U.S. aid, combined with the evidence of chemical weapons use, will finally persuade Russia to push the regime into a negotiated solution requiring Mr. Assad’s departure. It won’t: Moscow quickly rejected the U.S. chemical weapons dossier and will surely continue its own weapons deliveries to the regime.

Only if the balance of the war shifts decisively to the side of the rebels will an acceptable political settlement be possible. That, in turn, will almost certainly require a more robust U.S. intervention. A starting point would be for Mr. Obama to sign off on a Pentagon plan, reported by the Wall Street Journal, to create a no-fly zone in southern Syria, which would create a space for rebels to organize and train, for weapons to be delivered and for civilians to harbor. It’s possible this could be done with the use of Patriot missiles and planes that remained in Jordanian airspace.

White House aide Ben Rhodes argued to reporters Thursday that a no-fly zone in Syria would be costly, would become an open-ended commitment and would not change the situation on the ground. On the last point, U.S. intelligence reports seen by the New York Times suggest otherwise: They say there were 500 air-to-ground attacks against Syrian rebels and civilians in May alone.

As for the cost and the U.S. commitment, it’s time for Mr. Obama to recognize that the war in Syria threatens vital U.S. interests — from the fight against al-Qaeda to the security of Israel. The delay in arming the rebels has already steeply raised the cost of achieving an acceptable outcome; too weak an intervention now will merely do so again.