The Obama administration should resist the temptation to intervene more forcefully in Syria's civil war. A victory by either side would be equally undesirable for the United States.
At this point, a prolonged stalemate is the only outcome that would not be damaging to U.S. interests.
Indeed, it would be disastrous if Bashar Assad's regime were to emerge victorious after fully suppressing the rebellion and restoring its control over the entire country. Iranian money, weapons and operatives and Hezbollah troops have become key factors in the fighting, and Assad's triumph would dramatically affirm the power and prestige of Shiite Iran and Hezbollah, its Lebanon-based proxy — posing a direct threat both to the Sunni Arab states and to Israel.
But a rebel victory would also be extremely dangerous for the United States and for many of its allies in Europe and the Middle East. That's because extremist groups, some identified with Al-Qaida, have become the most effective fighting force in Syria.
If those rebel groups manage to win, they would almost certainly try to form a government hostile to the United States. Moreover, Israel could not expect tranquility on its northern border if the jihadis were to triumph in Syria.
Things looked far less gloomy when the rebellion began two years ago. At the time, it seemed that Syrian society as a whole had emerged from the grip of fear to demand an end to Assad's dictatorship.
Back then, it was realistic to hope that moderates of one sort or another would replace the Assad regime, because they make up a large share of the population. It was also reasonable to expect that the fighting would not last long, because neighboring Turkey, a much larger country with a powerful army and a long border with Syria, would exert its power to end the war.
As soon as the violence began in Syria in mid-2011, Turkey's prime minister, Recep Tayyip Erdogan, loudly demanded that it end. But instead of being intimidated into surrender, Assad's spokesmen publicly ridiculed Erdogan, while his armed forces proceeded to shoot down a Turkish fighter jet, before repeatedly firing artillery rounds into Turkish territory and setting off lethal car bombs at a Turkish border crossing.