After 9/11, many within the U.S. national security establishment worried that, following decades of preparation for confronting conventional enemies, Washington was unready for the challenge posed by an unconventional adversary such as al Qaeda. So over the next decade, the United States built an elaborate bureaucratic structure to fight the jihadist organization, adapting its military and its intelligence and law enforcement agencies to the tasks of counterterrorism and counterinsurgency.
Now, however, a different group, the Islamic State of Iraq and al-Sham (ISIS), which also calls itself the Islamic State, has supplanted al Qaeda as the jihadist threat of greatest concern. ISIS’ ideology, rhetoric, and long-term goals are similar to al Qaeda’s, and the two groups were once formally allied. So many observers assume that the current challenge is simply to refocus Washington’s now-formidable counterterrorism apparatus on a new target.
But ISIS is not al Qaeda. It is not an outgrowth or a part of the older radical Islamist organization, nor does it represent the next phase in its evolution. Although al Qaeda remains dangerous—especially its affiliates in North Africa and Yemen—ISIS is its successor. ISIS represents the post–al Qaeda jihadist threat.
In a nationally televised speech last September explaining his plan to “degrade and ultimately destroy” ISIS, U.S. President Barack Obama drew a straight line between the group and al Qaeda and claimed that ISIS is “a terrorist organization, pure and simple.” This was mistaken; ISIS hardly fits that description, and indeed, although it uses terrorism as a tactic, it is not really a terrorist organization at all. Terrorist networks, such as al Qaeda, generally have only dozens or hundreds of members, attack civilians, do not hold territory, and cannot directly confront military forces. ISIS, on the other hand, boasts some 30,000 fighters, holds territory in both Iraq and Syria, maintains extensive military capabilities, controls lines of communication, commands infrastructure, funds itself, and engages in sophisticated military operations. If ISIS is purely and simply anything, it