It remains unclear how many members AQAP actually has — perhaps a few hundred — because incidents are often attributed to it inaccurately. For example, the Abida tribe near Marib, an area in Yemen’s east rich in oil and natural gas, became enraged after a U.S. drone strike killed a senior sheikh in May 2010, possibly due to Saleh’s duplicity. In response, the tribe has severed the main road in the area, interrupted power supplies to Sana’a, and blocked oil exports — strikes that the Saleh regime regularly blames on al Qaeda. (In truth, the similarity of tactics often makes it difficult to determine whether tribesmen or jihadis are responsible for a particular attack.)

Similarly, the Islamists who recently established a so-called Islamic Emirate in the southern province of Abyan have denied that they are affiliated with al Qaeda, although they confess to having a common Islamist philosophy. Indeed, they have patrolled Jaar, one of Abyan’s major towns, in tanks captured from the Yemeni army — hardly the actions of al Qaeda militants living under the constant threat of missile attacks from U.S. drones. Yet the Saleh government has consistently labelled these Islamist insurgents as al Qaeda members ever since they took de facto control of Abyan. (They have, however, since been repulsed from their footing in Abyan’s capital, Zinjibar.)…

Yemen’s tribes and AQAP have far more potential points of friction than they do common cause. For starters, many of Yemen’s combative tribes are Zaydis, a pragmatic Shiite sect, for whom the fundamentalist Sunni members of al Qaeda have a vitriolic ideological aversion. Beyond that, the jihadis threaten entrenched tribal interests, such as the production and use of qat (a mildly stimulant leaf beloved by many Yemenis but abhorrent to Salafis) and the lucrative trade of smuggling drugs and alcohol into Saudi Arabia.