Eleven years after 9/11, al Qaeda is fighting back. Despite a focused and concerted American-led global effort—despite the blows inflicted on it by drones, SEALS, and spies—the terror group is thriving in the Arab world, thanks to the revolutions that swept across it in the last 18 months. And the group remains intent on striking inside America and Europe.

The al Qaeda core in Pakistan has suffered the most from the vigorous blows orchestrated by the Obama administration. The loss of Osama bin Laden eliminated its most charismatic leader, and the drones have killed many of his most able lieutenants. But even with all these blows, bin Laden’s successor, Ayman al-Zawahiri, is still orchestrating a global terror network and communicating with its followers.

Most importantly, al Qaeda’s allies in Pakistan, the Taliban and Lashkar-e-Taiba, which attacked Mumbai in 2008, are under no pressure. They continue to enjoy the patronage of the Pakistani intelligence services. Lashkar-e-Taiba has a global network with cells in America, England, and the Persian Gulf. Just this summer, the Saudis arrested a key Lashkar operator planning a new mass-casualty attack and extradited him to India.

But it is in the Arabian Peninsula that al Qaeda is really multiplying. Its franchise in Yemen has staged three attacks on America, including one at Christmas in 2009—the infamous “underwear bomber—that almost succeeded in Detroit. Its brilliant Saudi bomb maker, Ibrahim al-Asiri, is alive and has trained a cadre of students. The Yemeni regime is weak, the country is spinning into chaos, and al Qaeda is exploiting it. Now the U.S. is using drones almost as much in Yemen as in Pakistan.

The al Qaeda apparatus in Iraq, despite being decapitated several times, carries out waves of bombings every month. It has proven remarkably resilient. In North Africa, al Qaeda has allied itself with other Islamist extremists and taken over more than half of Mali, an area bigger than France. There it is training terrorists from Algeria, Morocco, Nigeria, and elsewhere. It has raided Muammar Gaddafi’s arsenal and is armed and dangerous.

A new al Qaeda franchise has emerged in Egypt’s Sinai Peninsula, where it is trying to provoke a war between Egypt and Israel. American troops in the multinational force keeping the 1979 peace treaty are at risk.

The fastest-growing al Qaeda operation is in Syria. Zawahiri ordered al Qaeda jihadists from around the world to go to Syria last February. They carried out seven attacks in March, and at least 66 in June. Al Qaeda won’t take over the embattled country, but it will thrive in the civil war and chaos there—and use Syria as a base for attacks in Jordan, Turkey, and Lebanon.

Attacking targets in America and Europe remains a high priority. Al Qaeda dispatched Chechen terrorists to Spain this year to attack Gibraltar. The Spanish unraveled the plot in August. Since 2009 al Qaeda plans to attack New York, Chicago, and Detroit have all failed due to good counterterrorism work, and good luck.

In fighting terror, our team has to stay lucky 100 percent of the time. Al Qaeda needs to be lucky only once.