A recurring feature in scorecards of counterterrorist successes is the reported death of someone described as the number three man in al-Qaeda. So many al-Qaeda number threes have been bumped off during the last several years that the job has come to be described as having the shortest life expectancy associated with any position anywhere. This could be an indication of the group's ability to regenerate and replace cadre. It could also reflect some puffery in counterterrorism—a tendency to exaggerate the significance of eliminating someone whose exact role was not known completely. It is very likely some of each.

With Osama bin Laden having himself been eliminated four months ago, the presumed hierarchy within al-Qaeda slides up a notch. There is bin Laden's deputy and successor, Ayman al-Zawahiri, and then there is everyone else. So it is now the title of number two that is associated with newly eliminated al-Qaeda heavyweights. Last week was the first reported killing, by a drone strike in Pakistan, of an al-Qaeda number two. The target was a Libyan named Atiyah Abd al-Rahman. There are numerous indications that Rahman was a significant figure in the group. But just as with the number threes, expect more elimination of number twos. The reasons for serial eliminations from this position will be the same as for the number threes.

The drone strikes do inflict damage on what is left of al-Qaeda central. They are a tool that cannot be discarded altogether, despite the significant downsides that must be carefully taken into account with each decision whether to use the tool. But the customary way of counting senior al-Qaeda scalps imputes structure to a terrorist group that exceeds our knowledge. It reifies a hierarchy that we are comfortable targeting and discussing whether or not it conforms to reality.

This manner of scalp-counting has other disadvantages regarding public understanding of terrorist threats to the United States. It accentuates the tendency to mistakenly equate such threats with a single group. The generally well-informed David Ignatius comments that the killing of Rahman “increases the likelihood that the organization’s center of gravity will shift from Pakistan’s tribal areas to one of the affiliates, such as the robust al-Qaeda in the Arabian Peninsula, based in Yemen.” In fact, the shifting has already occurred, and in a way that involves not just any one affiliate and that tends to undermine the whole idea of a “center of gravity.”

Notwithstanding the lessons that ought to have been learned from the elimination of all those number threes, the scalp-counting encourages a view of counterterrorism as a task of eliminating a fixed set of bad guys. It mistakenly looks at terrorism as particular groups of people rather than as a tactic that can be used by any group of people.

Finally, the focus on the vitality of particular individuals in a particular group encourages the overstating of how much terrorist threats of today are a matter of those individuals instigating, recruiting, and organizing other individuals and the understating of how much the threats result from the other individuals initiating contacts and actions out of anger over certain policies, conflicts, and situations. That in turn distorts understanding of what is and is not in the power of the United States to do to lessen the threat.