ASPEN, Colo.

President Obama’s finest moments in foreign policy, like the Osama bin Laden raid or the Libya intervention, resulted from close engagement and calculated risks.

His lapses come when he’s passive or AWOL — as in Syria. I’m generally a fan of Obama’s foreign policy, but on Syria there’s a growing puzzlement around the world that he seems stuck behind the curve.

The United States shouldn’t invade Syria. But we should work with allies to supply weapons, training and intelligence to rebels who pass our vetting.

I’m in Aspen for the annual meeting of the Aspen Strategy Group, a bipartisan group looking at international affairs, and I’m struck by how many strategists whom I respect think it’s time to move more aggressively.

William Perry, a secretary of defense under Bill Clinton, told me that if he were in the Pentagon today, he would be recommending a military intervention in Syria — conditioned on Turkey’s participation and without ground forces. Specifically, he said he would favor imposing a no-fly no-drive zone in northern Syria.
“This isn’t a full strategy, but it could facilitate the overthrow of Assad and have a real humanitarian benefit,” Perry said. “And if successful, it could help us influence the post-Assad government. If we sit by, we’ll be in no position to influence it.”

Madeleine Albright, who was secretary of state under Clinton, told me: “I’m for intervention, but it doesn’t have to be on-the-ground military intervention. We do have to get more involved in this.”

Albright said that the American intervention should be multilateral, but that the inability to achieve a Security Council resolution shouldn’t block action any more than it did in Kosovo in 1999. “We can’t afford to be in a cul-de-sac while people are being killed,” she said.

As I see it, there are three main reasons for action in Syria.
First, the longer the fighting goes on, the more it destabilizes the region. Syria is now in a civil war linked to the Sunni-Shiite divide in the region. The more deaths, the more refugees, the more revenge killing, the tougher it will be to put Humpty Dumpty together. The longer the war persists, the more risk of spillover into Lebanon, Iraq and Jordan.

Second, Assad is believed to have many tons of sarin and VX nerve agents. Those chemical weapons could end up in the hands of jihadis or on the global black market, and we should work with Syrian rebels to help secure them if necessary.

Third, there’s a humanitarian imperative. It appears that several times more people have been killed in Syria than in Libya when that intervention began, and the toll is rising steeply.

Protesters began peacefully but have been subjected to unspeakable violence. An iconic victim is a boy named Hamza al-Khateeb, who was apparently detained at an anti-Assad demonstration — and then sexually mutilated and tortured to death at the age of 13.

What can we do? One step would be for the United States to move naval forces off the Syrian coast, while Turkey and Israel moved more troops close to their borders with Syria. This would pin down Syrian troops so that Assad would have fewer forces available to murder his people.

Anne-Marie Slaughter, a Princeton scholar who previously served as a senior Obama administration official, has offered sensible proposals for action. She suggests that the United States and other countries provide antitank and antiaircraft weapons and perhaps air cover to commanders who protect civilians and eschew sectarian or revenge killings. Some Free Syrian Army commanders have signed such a code of conduct.

With our allies, we can also advise Syrian commanders that if they abandon Assad they may have a role in Syria’s future. If they go down with Assad, they won’t.

An intervention can always go awry, and there are legitimate concerns about the behavior of Syrian rebels. It is also true that an election year isn’t an ideal time for an intervention, although on this one Obama could work with Republicans to win bipartisan support.

Look, I’m no hawk. I was strongly against the Iraq war and the Afghan surge, and I’m firmly against today’s drift toward war with Iran. But Syria, like Libya, is a rare case where we can take modest steps that stand a good chance of accelerating the fall of a dictator. And after 17 months, there’s growing agreement that Obama should no longer remain a bystander.

“The Middle East needs U.S. leadership on Syria,” said R. Nicholas Burns, a former under secretary of state for political affairs, now a Harvard professor. “I’m a supporter of the president’s approach to the Middle East in general, but his administration has been entirely reactive on Syria. You hear from all the Arabs: ‘Where is the United States?’ ”
President Obama, your answer?