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.

Kennan described Marxist theory as a “highly convenient rationalization” for the revolutionaries’ own instinctive desire for power and revenge. ISIS, too, uses a particular and peculiar reading of Islamic texts to justify raping children, burning prisoners of war alive, and spreading its ideology through barbarism. And Kennan also observed how dictatorial power became necessary in the absence of popular support for the movement. There are of course limits to the parallels. Soviet power, in Kennan’s view, was not “adventuristic” and did not take “unnecessary risks.” ISIS, by contrast, is and does. But Kennan’s prescription for “the adroit and vigilant application of counter-force” against the Soviet Union applies to ISIS as well. (According to the historian John Lewis Gaddis, Kennan meant this counter-force to be primarily diplomatic and psychological, but subsequent interpreters have viewed counter-force in military terms.)

And just as containing the Soviet Union required much more than a strategy of hope, so too, containing ISIS will require fighting the organization’s spread with both military and diplomatic means. It took nearly 70 years for the Soviet Union to collapse, which occurred, in large measure, as a result of internal economic forces and the Soviet people’s discovery that what they had been promised was available only to their leaders. ISIS, too, will no doubt eventually collapse as a result of its equally false utopian promises and difficulties delivering even rudimentary human needs, such as healthcare. In the meantime, the United States and its allies need to implement a continuously evolving strategy of robust containment.

The United States and its allies can and should establish a no-fly zone over Northern Syria to protect the Syrian people from their own president’s bombing raids, since Assad’s depredations are a powerful source of recruitment for ISIS. They can and should deploy more special-operations forces. They can and should get better at sharing intelligence among themselves, and will have to reconsider the post-Snowden anti-surveillance mood. The “expeditionary force” announced recently by Defense Secretary Ashton Carter will provide an important enhancement to current intelligence capacities. There are compelling reasons to expand the number of ground forces in Iraq above the current 3,500 troops, but it would be far better if those forces were made up, not of “crusaders,” but Sunni Arabs. But it’s necessary to be realistic about the impact of these efforts, which will not defeat the Salafi jihadist ideology that fuels ISIS and its “expansive tendencies” unless and until the international community finds a way to undermine its appeal.

On this ideological dimension, too, Kennan was insightful in observing that “world communism is like malignant parasite which feeds only on diseased tissue;” ISIS is spreading into “diseased tissue” in weak states around the world as well as in weak parts of strong states, such as the poorly integrated banlieues of Paris. Containing the group requires recognizing its dual nature. ISIS is both a totalitarian proto-state that controls territory and is trying to spread its “caliphate” into ever more regions where state structures are weak, as well as a global terrorist organization bent on goading the West to counterattack.

In the latest issue of Dabiq, ISIS’s online magazine, the organization refers to these two goals as “options.” Although they’re contradictory—inciting attacks on its own territory hardly helps ISIS maintain its state—there is one strategy, outlined in a previous issue of Dabiq, that serves both goals: to eliminate the “grayzone” of moderate Islam and to force Muslims living in the West to either join ISIS or “apostasize and adopt the kufri religion.” It’s a strategy of “polarization” spelled out in in the jihadist text The Management of Savagery, which promotes turning Muslims against one another, inciting internal divisions within the West, and turning the West against Islam.

What can those of us in the West do to help ISIS achieve this goal? In other words, what’s the best way not to contain ISIS?

Fail to recognize that ISIS’s most numerous victims are Muslims.

Conflate ISIS’s ideology with Islam. (Yes, ISIS justifies its brutality by referring to religious texts. But that is true of religious terrorists, across religions. Religious texts are full of contradictions—some of which promote the protection of civilians in war, some of which can be interpreted as a justification for terrorism.)

Conflate the victims of jihadist brutality, now desperately seeking refuge in the West, with the perpetrators from whom they are trying to escape.

Urge Nuremburg-type laws for Muslims, requiring them to register with the state—or call for keeping them out altogether.

Send in the 100,000 troops it would take to defeat ISIS in Syria and Iraq, while failing to address the underlying problems of disenfranchised Sunni Muslims, leaving an opening for ISIS or another group like it to rise again.

Kennan’s recommendations, tailored to a completely different challenge, are proving prescient in the ISIS era. In particular his exhortation that “our first step must be to apprehend, and recognize for what it is, the nature of the movement with which we are dealing,” bears heeding. Because just as much as Kennan’s texts contain clues about how to contain ISIS, ISIS’s own texts spell out clearly how not to.