Illustration by Bloomberg View
Illustration by Bloomberg View

The al-Nusra Front in Syria pledged formal allegiance to al-Qaeda last week. Together with the alarming escalation in refugees fleeing the country, this pact demands a forceful change in the diffident strategies of the U.S. and Europe toward the conflict.

The U.S. has good reasons for not wanting to own another war in the Middle East, and we support them. But does anyone believe the U.S. could stand aside if al-Qaeda were to gain control of all or part of a state that has chemical weapons and Scud missiles and shares borders with Iraq, Israel, Jordan, Lebanon and Turkey?

Al-Nusra’s pledge to al-Qaeda offers an opportunity, however. The group’s terrorist bombing tactics and imposition of radical Islamist rules have begun to erode its popular support and ties to other fighters. Last month al-Nusra began to fight with another less radical rebel group in northern Syria. The more al-Qaeda and non-al-Qaeda rebels define themselves against each other, the less difficult it will be for the U.S. and its allies to identify fighters they can arm and work with.

Other pieces now falling into place may ease the path to action. The Syrian opposition is forming a government, which may help with legal hurdles to greater intervention. The European Union’s arms embargo will expire at the end of May and, thanks to opposition by France and the U.K., is unlikely to be renewed. Opposition groups not linked to al-Qaeda are gaining control over a patch of southern Syria that borders Israel and Jordan.

The U.S. is shifting its position, but late and slowly. It is an open secret that U.S. personnel are training rebels in Jordan, and Secretary of State John Kerry has said the U.S. will start sending nonlethal aid directly to the Free Syrian Army, though exactly what the U.S. will provide remains unclear.

The U.S. and its allies should make their April 20 meeting in Istanbul a watershed. First, they must close the shameful, and increasingly dangerous, shortfall in funding for the humanitarian aid operation. The United Nations has registered more than 1 million Syrian refugees and estimates that 3.6 million people have been displaced within the country -- and yet it has received less than a third of the $1 billion it was promised. The crisis threatens to destabilize Jordan and Lebanon.

Second, they should use the meeting to consolidate control over the disparate sources of arms and training for the Free Syrian Army. President Barack Obama’s meetings with leaders from Qatar, Turkey and the United Arab Emirates over the next month could provide a useful opportunity to advance this approach.

Third, they should seize on the common threat posed by al-Nusra to persuade Russia to stop arming and funding Assad and his regime. Russia has two primary concerns -- that Syria shouldn’t become another scene of unilateral U.S. intervention in the Middle East, and that the country shouldn’t fall to chaos or Islamists radicals. By now it is clear the U.S. has no desire to repeat a Libya-style intervention in Syria, and that it shares Russia’s goals.

A cease-fire deal and heavily armed peacekeeping force approved by the UN remains the most desirable next step for Syria. That’s difficult, given the uncompromising stances of both Assad and the rebel fighters. But Assad and Russia should know that the next step, absent a Security Council agreement, will be to increase arms supplies to the opposition, including anti-aircraft weapons, and to create buffer zones to shelter fleeing civilians, beginning in the South along the Jordanian border.

All actions involve risks. In this case, so does the status quo. When a quarter of a nation at the heart of the Middle East has been displaced, and al-Qaeda is close to acquiring weapons of mass destruction, equivocation is no longer safe or acceptable.

To contact the Bloomberg View editorial board: view@bloomberg.net.