With the ongoing tension over Russia’s annexation of Crimea, now would be a good time to talk about the biggest myths people believe about the origins of secessionist movements around the world (even though Crimea is a case of irredentism not secessionism).

1. Myth: Secession is contagious. Back in the 1990s, journalists worried a lot that the disintegration of the Soviet Union, Czechoslovakia, Yugoslavia, and Ethiopia heralded some broader worldwide trend toward the splintering of the state. Even some scholars indulged talk of our “neomedieval” future of microstates. Now, with secession referendums in Scotland and Catalonia on the docket, a secessionist party gaining support in Quebec, that online referendum in Veneto, and recent events in the post-Soviet space, I’m seeing similar questions about whether this is a new “trend.”

   Fact: Secession happens because of particular circumstances, not contagion. Scholars have looked at the evidence every which way, and in no…