Wintertime is peace time, or so goes the conventional wisdom in the South Caucasus. This thinking is being challenged this week: On Tuesday, in cold temperatures, Azerbaijan reportedly suspended again the gas supply to Nagorno-Karabakh, a disputed Armenian-populated region, amid an already ongoing blockade. With E.U. monitors set to depart on Sunday the borderlands that Azerbaijan attacked three months ago, the populations of Nagorno-Karabakh and all of Armenia are left pondering the next moves of Azerbaijan’s dynastic president Ilham Aliyev. But if Aliyev does go further, it wouldn’t be the area’s first winter war—and the other exception to that historical rule is an instructive one.