They’re only about 10% of the rebel forces attempting to dislodge that noted reformer Bashar al-Assad, CNN’s Nick Paton Walsh reports, but Jabhat al-Nusra is the most effective and powerful part of the insurrection against the Iranian-backed dictator. The only problem for the US is that they’re closely affiliated with al-Qaeda in Iraq, which has been attempting to overthrow the democratically-elected government in Baghdad, too. If this is starting to sound familiar, just think …. Libya:

The Christian Science Monitor has more background on the “foreign terrorist organization” that’s staffed by veterans of some old, familiar places:

The speed with which the US government moved to designate a fairly new group that has never attacked US interests and is engaged in fighting a regime that successive administrations have demonized is evidence of the strange bedfellows and overlapping agendas that make the Syrian civil war so explosive.

The State Department says Jabhat al-Nusra (or the “Nusra Front”) is essentially a wing of Al Qaeda in Iraq, the jihadi group that flourished in Anbar Province after the US invaded to topple theBaathist regime of secular dictator Saddam Hussein. During the Iraqwar, Sunni Arab tribesmen living along the Euphrates in eastern Syria flocked to fight with the friends and relatives in the towns along the Euphrates river in Anbar Province. …

The Nusra Front has gone from victory to victory in eastern Syria and has shown signs of both significant funding and greater military prowess than the average citizens’ militia, with veterans of fighting in Iraq, Afghanistan, and Libya among its numbers.

The US of course aided the fight in Libya to bring down Muammar Qaddafi. In Afghanistan and Iraq, the chance to fight and kill Americans was the major drawing card.

Their presence might tempt Barack Obama to send in US forces to keep chemical weapons out of the Nusra Front’s hands:

The Obama administration appears eager for Assad to fall, but is also afraid of what might replace him, not least because of Syria’s chemical weapons stockpile. If the regime collapses, the aftermath is sure to be chaotic, much as it was in Libya, where arms stores were looted throughout the country. The presence of VX and sarin nerve gas, and the fear of Al Qaeda aligned militants getting their hands on it, has the US considering sending in troops to secure the weapons.

That’s the context in which today’s designation was made – part of an overall effort to shape the Syrian opposition to US liking, and hopefully have influence in the political outcome if and when Assad’s regime collapses. But while the US has been trying to find a government or leadership in waiting among Syrian exiles, Nusra has been going from strength to strength. Aaron Zelin, who tracks jihadi groups at the Washington Institute for Near East Policy, notes in a recent piece for Foreign Policy that 20 out of the 48 “martyrdom” notices posted on Al Qaeda forums for the Syria war were made by people claiming to be members of Nusra.

This Arab Spring-destabilization business is pretty dangerous after all, no?