Russia’s annexation of Crimea, de facto or de jure, is likely to spur violence in the peninsula. “Crimean Tatar representative” in Lviv, Ukraine Alim Aliyev is quoted as saying, “Tatars will launch a guerrilla war against the Russian forces if they do not pack up and leave the region.” While he could be communicating a mere bluff, I wouldn’t count on it, and I doubt Putin will either. Crimean Tatars currently have a low risk of secessionist insurgency, because they are just 12% of the region’s population, but they also see themselves as the indigenous population of the region and deny any other ethnic group’s claims to a homeland in the region. For those reasons, and because of a history of repression at the hands of Stalin, Crimean Tatars support Ukrainian sovereignty over Crimea and reject the small ethnic Russian majority’s claims. If Russia effectively annexes Crimea, Tatar violence is likely to flare up. While the massive Russian military will be able to crush organized resistance, I doubt Putin wants to create another Chechnya, with the attendant risks of future terrorist attacks on Russian civilians.

Steve Saideman and Bill Ayres’ research suggests that irredentism is rarely consummated because it requires an infrequent coincidence of interests: a minority that wants to be rescued and a powerful state willing to pay costs to rescue it. Rescuing Crimea is likely to have significant long-term costs for Russia, and if Putin acts rationally, he will prefer a negotiated settlement permitting a military withdrawal from the peninsula over any kind of annexation.

In other news: the Crimean referendum will have two options: annexation by Russia and independence. Rejecting both and remaining within Ukraine is not an option for voters.