How can the war in Syria be stopped?

Updated 9:53 AM EDT, Tue September 15, 2015

Story highlights

More than 200,000 Syrians have died in the country's civil war; hundreds of thousands more have fled

Four years in to the conflict, the international community is still struggling to find a workable solution to end the fighting

(CNN) —  

We are 1,645 days into the Syrian conflict. Half the country’s people are on the move, and more than 200,000 have died. ISIS – more radical than al-Qaeda – has seized parts of the country’s north. Chemical weapons are now often used.

So what would it take to stop the war, or at least calm it enough to enable some Syrians to go home?

A full U.S. or Western invasion is not likely to happen, nor would it alleviate the problems. But none of the more obvious other options offer much hope either:

1. Arm the Syrian opposition and remove the Assad regime with military force

This option was toyed with by Western leaders in 2013 when they debated punitive strikes against the Assad regime for the use of chemical weapons in Ghouta, but it would be pretty ugly now.

NATO airstrikes would probably cripple the Assad regime quickly. But what would happen to the people in government strongholds – the capital, Damascus,and the Mediterranean coastal enclaves of Tartus and Latakia?

It’s pretty likely Syrian opposition forces would sweep in to those big population centers, where there are many Alawi and Shia loyal to the regime. And those opposition forces have radicals – including the al-Qaeda linked Nusra Front – in their ranks.

At the very least, there would be a huge refugee outflow into Syria’s already overcrowded neighbor, Lebanon; at worst a massacre.

2. Create a no-fly zone and a safe-area in Syria’s north. Let Syrians return there, receive aid and rebuild, while the rest fight it out

The Syrian opposition and Turkey have long wanted to create such an area, with the backing of Western air power. The hope is the Assad regime would stop its indiscriminate bombing of the north and that Syrian opposition moderates would take over, allowing in aid.

This could possibly have worked when first proposed in 2013, but two years later, the moderate forces of the Syrian opposition are at their weakest yet.

Ahrar-al-Sham, one of the largest groups of opposition fighters, is considered by many critics as too close to its battle allies, al-Qaeda franchise, the Nusra Front. They have joined together to create the Jaish al Fateh, which is moving fast against the regime in the north, particularly towards the coastal town of Latakia.

Other moderate forces are either weak, or face similar allegations. Even the U.S.-vetted, armed and trained New Syrian Force, was a mere 54 in number when the Nusra Front attacked their base, killing and capturing some of their fighters.

There is a risk that, in taking out regime air power with a no-fly zone, NATO could end up militarily benefiting al-Qaeda in their fight against the regime.

3. Accept that Assad is a necessary evil and back him so parts of Syria at least stay together

Is this – preferred by Iran and Russia for their own differing geopolitical reasons – the best of a series of awful options? Not really – it fails to deal with the fundamental reason for the uprising, and the principle cause of civilian casualties in the country, the indiscriminate bombing by the regime.

U.S. President Barack Obama said Assad had to go back in 2011, but in the last months, as Washington hammered out a nuclear deal with Assad’s main backer, Iran, the U.S. has been accused of softening its tone out of political expediency.

Now the subject of Assad’s departure is center stage once more. There is a reason for that: unless he goes, hardly any of the rebels in the north will be persuaded to stop fighting, no matter what any distant political deal offers them. Assad’s bombardment and massacres are at the root of the uprising.

There is a massive paradox here for Washington, which is at the heart of its dilemma: even if they could spend huge amounts of political capital to persuade Russia, Iran and China to turn their backs on Assad, that won’t stop the war overnight. There isn’t even an obvious alternative in the frame who could lead an interim government in Damascus.

But if they let Assad stay in place, the war will continue too, fueled by a desire for vengeance among Syrians who’ve seen their loved ones massacred over four years, and think the U.S. no longer cares to defend them. It’s a lose-lose for Washington

4. Split the country into four different enclaves: Kurdish, ISIS, other opposition, and regime, and hope they eventually stop fighting

Hard to do without the sides agreeing on borders, and the above four groups are in a fight to the death now. And there is no outside military force willing to impose new boundaries.

5. Keep doing what you are doing: drone and airstrikes against ISIS, and do as little as you can with the Syrian opposition to escape being told you’re doing nothing

This seemed like the ideal option, to the White House at least. But now millions of Syrian refugees have begun to realize they won’t be going back to Syria any time soon, and that a better life might be possible in Europe. Or, if they are poor, they are realizing their U.N. food aid is running out.

Drone strikes against ISIS do fit with Washington’s basic and immediate national security goals, but they won’t stop the security threat to Europe, which has in the past proven a launching pad for jihadis into the United States.