The West can defeat the Islamic State in the territory it now controls. But it would take a massive ground invasion, and the results would be temporary at best. As Barry Posen argues in his recent Atlantic essay, “American attempts to reorganize the politics of other countries by the sword have foundered on nationalist resistance to outsiders, unreliable local allies, deeply embedded cultural practices, and the inherent crudeness of the military instrument.” The Islamic State of Iraq rose again after it was beaten back during the surge of U.S. forces into Iraq beginning in 2007; as long as Sunni Arabs continue to feel unsafe in their homes, jihadist organizations will step in to “protect” them from harm.
Hence Posen, among others, has argued that the United States and its allies should try to contain the group. In considering how to do this, it’s instructive to look at the intellectual roots—and the results—of the containment strategy as laid out by George Kennan in 1946 in his “long telegram,” later published under the pseudonym “X” as “The Sources of Soviet Conduct.” As I noted in Lawfare recently, he described the Marxists’ problems spreading their movement, even within Russia, and noted that “Soviet society may well contain weaknesses which will eventually weaken its own total potential.” For this reason, as well as to counter the Soviet Union’s “expansive tendencies,” he advocated a policy of “long-term, patient but firm and vigilant containment” rather than an outright effort to seek its defeat.