Syrian President Bashar Assad's brutal war against his domestic opponents has taken some 70,000 lives so far and reduced much of the country to rubble, yet there's no sign either side has gained a decisive advantage in the two-year-old conflict. The European Union's decision this week to lift its ban against arming the Syrian rebels is ostensibly aimed at prodding the combatants into a negotiated settlement, but the effect could be just the opposite if it encourages both sides to dig in their heels even deeper.

President Barack Obama rightly worries that sophisticated weaponry sent to Syria's armed opposition could easily end up in the wrong hands if Islamist groups affiliated with al-Qaida eventually emerge as the strongest rebel faction. The problem is there's no way to ensure that won't happen in the absence of a negotiated settlement among the combatants, and paradoxically the EU's recent action may have made such an outcome less rather than more likely.


The Obama administration remains in a difficult spot after acknowledging evidence of chemical weapons use in Syria, something the president had previously described as a "red line" warranting a change in U.S. policy. Such a statement must be backed up, yet it is unclear that any American military involvement short of full-scale war would succeed in bringing the conflict to a close. The much more promising response was the American effort to work with Russia to set up peace talks between the Syrian government and the opposition in Geneva next month.

Russia reacted sharply to the EU's action Tuesday, charging its purpose was to scuttle negotiations. At the same time, the Russian government said it would continue arms shipments to the Assad regime. If the EU eventually does arm the rebels — a decision that apparently is still months away — the result could simply be an intensification of the fighting that leaves the military balance on the ground unchanged.

Given the prospect of a bloody stalemate that could go on for years, it's imperative for Secretary of State John Kerry to convince his Russian counterpart that neither of their countries' interests would be served by a protracted conflict that threatened to destabilize the entire region. That won't be easy. Russia has been the Syrian government's strongest supporter, even though it claims its allegiance is to the country's territorial integrity, not to Mr. Assad personally. Yet its pledges of support undoubtedly have strengthened the Syrian leader's resolve to hang onto power at all costs.

Those costs include the potential for the conflict to spill over Syria's borders into neighboring Lebanon, whose militant Hezbollah movement has dispatched fighters to bolster the Assad regime in Syria. Israel recently entered Syrian airspace to carry out strikes against advanced Russian surface-to-air missiles stored at a research facility outside Damascus, which it claimed Mr. Assad might transfer to Hezbollah, its sworn enemy.

Israel also issued a blunt warning to Russia that it will act to prevent Syria from acquiring such weapons in the future. And last week Syrian government forces briefly exchanged gunfire with Israeli troops on the occupied Golan Heights inside Syria. Such incidents clearly have the potential to spin out of control as a result of miscalculation or accident, with unpredictable consequences.

That's why the peace talks tentatively set for next month may offer the last, best chance for resolving Syria's civil war before both sides escalate the conflict. But that will depend largely on whether Russia is willing to pay more than lip service to the notion that Mr. Assad can be persuaded to relinquish power immediately and allow the formation of a transitional government representing all the country's religious and ethnic factions. That's a key demand of the opposition. Mr. Obama needs to urge America's European allies as well as the Russians to give diplomacy a chance before opening a new spigot of advanced weaponry.

President Obama rightly has been reluctant to intervene in Syria beyond providing humanitarian assistance and nonlethal military aid to the rebels, who are deeply divided and include groups affiliated with al-Qaida. The last thing the U.S. wants is for weapons supplied by it and its European allies to one day be turned against us. That's why stopping the fighting now is crucial if the U.S. hopes to avoid deeper involvement in Syria's bloody civil war and its aftermath, and that can only happen through a diplomatic settlement leading to a peaceful transition of power that's backed by Russia.