When France took up the challenge of defeating al Qaeda’s franchise in northern Mali, it took on a very well-armed and well-funded group. Since the fall of the Taliban in Afghanistan in 2001, al Qaeda hasn’t had a foothold this significant, and its offshoot in Africa poses a serious threat to not only Africa but the West, too. While Washington, for now, has elected to take the backseat in this fight, the United States has a big stake in the outcome.

Al Qaeda in the Islamic Maghreb is a group with ambitions. Similar to its partnership with the Taliban in Afghanistan, the group last year successfully gained the support of Ansar al Dine, a local jihadist group in Mali, and together they now control a huge expanse of territory. In the same way that al Qaeda and the Taliban destroyed Afghanistan’s historical treasures in the years leading up to 9/11, they are destroying the cultural heritage in the fabled city of Timbuktu. And as it happened in Afghanistan, jihadists from across the region are now flocking to Mali to get access to training, money, and weapons.

The jihadi offshoot in the Maghreb used to be ranked as one of al Qaeda’s weaker franchises. Created from an Algerian terrorist group in 2006, the group at first focused on petty criminal enterprises, such as kidnapping Westerners traveling in the remote deserts of Algeria, Mali, Mauritania, and Niger. However, the ransoms paid into what became a sizable war chest, counting over $100 million. And in 2007, it launched its first successful larger scale attack: blowing up the United Nations headquarters in Algiers with twin car bombs.

After the fall of Libyan dictator Muammar Gaddafi in 2011, the group began to accumulate huge amounts of weapons from the North African country, which remains unstable. This windfall was followed up by the strategic partnership with Ansar al Dine that allowed the two groups to sweep out government forces from northern Mali, before turning on a Tuareg independence movement, an erstwhile ally, gaining control of an area of the Sahara the size of Texas. The mix of al Qaeda in the Maghreb, Ansar al Dine, and the Tuareg rebels is combustible. After the looting of the Gaddafi arms depot in Libya, they are all very well armed; indeed, al Qaeda in the Maghreb is likely the best armed al Qaeda franchise operating in the world today.

It is also the fastest-growing al Qaeda franchise in the world today. And most of Mali’s neighbors are horrified at what is taking place in the north. The Moroccan foreign minister told me recently that the jihadists present the greatest threat to regional stability in more than a decade. As previous experiences in Afghanistan, Iraq, and elsewhere have taught us, once al Qaeda establishes a presence in a failing state, it becomes very difficult to dislodge.

So France, the former colonial ruler of Mali, has stepped into the fray. This weekend Paris stopped an advance by the jihadists on the capital, Bamako, and is now attacking bases in the north.

The intervention is a mixed blessing. The French know more about Mali than anyone else. They should—it is their creation—an artificial state whose borders Paris created. French intelligence has better insights into Tuareg and jihadi militants than their counterparts in the U.S. or the U.K. But Paris also carries a lot of baggage from the colonial era, and many Africans and Arabs resent French interference.

Algeria, Mali’s big neighbor to the north with the largest army in Africa and extensive spy networks across the Sahara, is especially sensitive and nervous about the French campaign. Algiers opposed NATO’s role in Libya and now blames NATO for starting the Mali mess.

So what should the United States do? Well, Washington can help with diplomatic efforts in the United Nations and elsewhere.

Secretary of State Hillary Clinton weighed in with a visit to Algiers last year; after calling the French plan for Mali intervention “crap” last month, the U.N. Ambassador Susan Rice has secured the organization’s blessing for fighting AQIM.

Going forward, American drones and other surveillance assets should assist the French, who also, urgently, need more smart bombs and munitions, because it is clear al Qaeda will strike back. It can kill hostages and kidnap more. A more horrifying scenario to contemplate is a mass casualty attack in France itself. The campaign launched from Paris last week is not without risk. And French intelligence services are closely monitoring the more than 5 million Algerian émigrés in the country. Al Qaeda’s emir, Ayman al-Zawahiri has been calling for a 9/11 style attack in Paris for years now.

If its group in the Maghreb has sleeper cells in France, now is the time they may be activated.