A member of the Free Syrian Army stands guard at a checkpoint they took over early on Monday after clashes with pro-government forces in Salqin city in Idlib October 22, 2012. REUTERS/Asmaa Waguih One of the biggest arguments against further U.S. support of the Syrian opposition is that "the rebels are terrorists aligned with al Qaeda."

It is a claim Syrian President Bashar al-Assad has made over and over during the 29-month conflict.

But the notion that the Syrian opposition is dominated by al Qaeda is a myth.

Expert assessments

“They have a presence, and they’ve captured some territory. But [al Qaeda fighters are] in the minority," Major Issam Rayyes, a former Syrian Army communications officer who defected in June 2012 and now serves the Free Syrian Army (FSA), told The Weekly Standard. "Congress is making a mistake in thinking the opposition is al Qaeda.”

Liz O'Bagy, an Institute of The Study for War researcher* who made trips to various parts of Syria in the last year, wrote in The Wall Street Journal that "the war in Syria is not being waged entirely, or even predominantly" by extremist Islamists linked to al Qaeda.

O'Bagy's post has been criticized for her links to "moderate" rebels — which O'Bagy defines as those who have respected women's and minority rights while calling for a civilian government — nevertheless, jihadist experts agree that the fear of an "al Qaeda takeover" is exaggerated.

"Rebel units are distributed across a broad ideological spectrum, with secular units at one pole and Salafi jihadists at the other, and most falling between the two," according to a new report by experts Jeffrey White, Andrew J. Tabler, and Aaron Y. Zelin of The Washington Institute. "A major differentiation among Islamic units is between those that are Islamic with a national or Syrian agenda and those with a global jihadist mission."

The Institute of the Study of War

Zelin estimates that 5,000 to 10,000 fighters make up Nusra, which wants to establish an Islamic Caliphate in the country's north.

Zelin, who runs the website Jihadology, estimates that 5,000-10,000 foreign jihadists have arrived in Syria and that about 1,000 have been killed in the fighting.

O'Bagy estimates that supporters of Jabhat al-Nusra and ISIS — the two main al Qaeda-linked groups — probably involve about 5,000 to 7,000 fighters while the number of rebels participating in offensive operations is about 80-100,000 rebels.

So a subset of Syrian rebels are certainly linked to al Qaeda, but terrorists make up about 10% to 20% of the opposition.

Anecdotal evidence

Two stories, one from an FSA fighter and one from an ISIS fighter, shed light on why the Syrian rebel picture is so complex.

Maher is "a member of Liwa al-Islam, the strongest rebel brigade in Damascus province, which counts both the Free Syrian Army (FSA) and the jihadist Jabhat al-Nusra as allies."

A former university student, Maher joined Liwa al-Islam after he beat a security officer unconscious for beating up a woman and the security forces subsequently raided the office he shared with other Damascus activists.

From Syria Deeply:

The goals of Liwa al-Islam are the same [as those of the FSA]: to remove the current government and create an alternative that would be formed by the people who have been working for it most effectively on the ground. Most of these people identify as Muslims.

... the Islamic State of Iraq and Syria does not exist on the ground as it does in the media. They are concentrated in the north, where you often have foreign fighters entering from outside Syria. In Damascus and its suburbs where I am, they are practically nonexistent.

Farhan al-Juma is "a fighter with the al Qaeda-backed group the Islamic State in Iraq and al-Sham (ISIS)" because he because he thinks that they are the most effective fighting force for the time being.

“As a battalion, we support ISIS, but we haven’t pledged allegiance. Once Syria is free we are able to walk away,” al-Juma told Syria Deeply. “It is up to each fighter whether they will be loyal to ISIS or not.”

From Syria Deeply:

As I leave, he shakes my hand. I am a woman. “Would I do this,” he asks, “if I was al-Qaida?”

So Maher is an Islamic FSA fighter with a Syrian agenda who respects women's rights. And Farhan is an Islamic ISIS fighter with a Syrian agenda who respects women's rights.

Both may be considered "extremist," but neither is al Qaeda and both actually fit O'Bagy's definition of a "moderate."

All in all, while al Qaeda-linked rebels are nation-building in northern Syria, an increasing number of Western-backed Syrian rebels are fighting to unseat Assad in the capital.

*O'Bagy has been fired from ISW for lying about having a PhD.