The story: Apparent Russian support for a controversial corridor linking Azerbaijan to its Nakhchivan exclave has triggered outrage in Tehran. The proposed route has long been opposed by Iran as it would sever the country’s land connection to Armenia. The flare-up between Moscow and Tehran highlights lingering points of contention, even as the two sides have developed unprecedented military cooperation since the Russian invasion of Ukraine. Though the Islamic Republic favors strong ties with the Kremlin, tensions could worsen if...