In killing 130 civilians in Paris—the worst such attack in France since World War II—ISIS has forced us to contend, once again, with the question of the “rationality” of self-professed ideologues. Since it wrested the world’s attention with its capture of Iraq’s second-largest city in June 2014, the extremist group has prioritized state-building over fighting far enemies abroad. This is what distinguished ISIS: It wasn’t just, or even primarily, a terrorist organization. It had an unusually pronounced interest in governance. As Yale University’s Andrew March and Mara Revkin lay out in considerable detail, the group focused its energy on developing fairly elaborate institutional structures in the territory it controlled within Iraq and Syria. ISIS wasn’t simply making things up as it went along. It may have been mad, but there was a method to the madness.

But why, then, attack France—one of the more militarily aggressive Western powers—and potentially provoke a massive retaliatory response that would threaten the very “caliphate” it had spent so much time building? Care is needed in drawing conclusions from this apparent shift in targeting. ISIS has always had international ambitions; it was more a question of when, not if. Part of the challenge is in divining why exactly ISIS chose to stage these attacks at this particular time. And this raises a difficult set of questions: To what extent, in the wake of the Paris attacks, should ISIS be thought of as rational, and how, in turn, should that inform efforts to understand the group and develop a strategy to counter it?