No country opposes the Iraqi Kurdish referendum more than the Islamic Republic of Iran. The reason is clear: Iranian leaders fear the precedent that Iraqi Kurds might set for Iran’s own restive Kurdish population.

With Soviet help, Kurdish nationalists carved the first modern Kurdish state out of the chaos of post-World War II Iran, declaring the self-styled Mahabad Republic on Jan. 22, 1946. It managed to survive for a year before Reza Shah — the father of the Iranian leader ousted in the 1979 Islamic Revolution — rallied his forces and crushed the would-be Kurdish state. Mulla Mustafa Barzani, father of de facto-Iraqi Kurdish leader Masoud Barzani, was one of four generals serving the short-lived republic.