The subsequent failure of the West to seriously aid or arm secular and mildly Islamist commanders left the field open to militants, who received floods of cash from private donors in the Arab Gulf. Now Assad is sitting pretty, claiming he is the only barrier to a jihadi takeover of Syria, and totally unwilling to negotiate with the remaining moderates, who continue to lose ground.
The result: While global attention focuses on groundless "diplomacy" and on the arrival of international chemical weapons inspectors, the real danger lies elsewhere. A new safe haven for al-Qaeda-linked jihadis and local Islamists is being established in territory that runs along the north and east of Syria and spreads into western Iraq.
Thousands of foreign fighters from Europe and the Middle East are flowing into this lawless area in hopes of establishing a virtual Sunni emirate - like the radical Islamist havens in Afghanistan under the Taliban, and those that remain in northwest Pakistan. However, this wannabe emirate is not in the remote mountains of South Asia but near the Mediterranean, Israel, and Europe. It also has an extensive and porous border with Turkey, a NATO nation.
When I visited an Islamist base in Syria last fall, near the Turkish border, I interviewed a red-bearded citizen of Belgium; there are reportedly many more from Belgium and other European and North African countries. These jihadis will one day return to Brussels, or to Egypt, or Tunisia, etc., revved up with radical ideology and military skills.
Equally dangerous, the jihadis in Syria are stirring up tensions inside neighboring countries, including Lebanon, Jordan, and Turkey, and are trying to ignite Sunni-Shiite tensions across the region. A prime target is Iraq, whose long and hard-to-protect border abuts Syria.
"There is a great danger of a spillover from Syria," says Hoshyar Zebari, the long-serving Iraqi foreign minister; he has been urging Washington to help Iraq to strengthen its border security. Over lunch in New York, he told me: "The movement of terrorist networks across the border is a daily affair."
As Zebari laid out, the Syrian regime has a long track record of aiding Islamist terrorists. In the mid-2000s, the Assad government helped al-Qaeda and other terrorist forces that were trying to overthrow the Iraqi government, letting them base in Syria and cross freely into Iraq. "Just a few years ago, we sought to hold the Assad government accountable before the U.N. Security Council for its support of terrorism," he said ruefully, but not even the United States would help.
When al-Qaeda in Iraq was defeated by U.S. and Iraqi forces in the late 2000s, some of its cadres found safe haven in Syria, helped by Assad's intelligence agencies. Now, those Sunni jihadis have teamed up with Syrian Islamists to fight against the Shiite regime of Assad. Meantime, within Iraq, they are trying to revive the Sunni-Shiite civil war with a wave of suicide bombs.
The proper Western response to this jihadi threat must be more proactive then sticking to fruitless diplomacy. Here are three actions that could be taken immediately.
One, give more help to Syria's neighbors, with refugee flows and border protection. Zebari, a Kurd, told me there are more than 200,000 Syrian refugees in Iraqi Kurdistan, which has received little aid from outside (or from Baghdad). He also told me that Washington is finally ramping up intelligence and other assistance for Iraqis along the Iraqi border, including training Iraqis on the use of drones.
Second, work to cut off aid from the Gulf to jihadi groups in Syria. According to William McCants of the Brookings Institution's Saban Center, who follows this issue closely, "a lot of the money is coming from just a few well-connected families," especially in Kuwait.
Third, be more serious about helping moderate rebel commanders. Only if they gain more purchase on the battlefield might Assad engage in serious talks to end the war.
Time is short. "The longer it goes on, the more explosive it becomes for Syria's neighbors," says Zebari. The extremist minority within Syria must be dealt with firmly before it precipitates the country's collapse.
E-mail Trudy Rubin at email@example.com.