Iran’s supreme leader Khamenei killed. What comes next is unclear and not easy

Since the 1979 overthrow of the Shah of Iran, the Islamic Republic of Iran has remained a longstanding geopolitical challenge for the United States. The recent killing of Supreme Leader Ayatollah Ali Khamenei has been viewed by some as a chance to topple the ruling ayatollahs. Yet experts warn that replacing Iran’s leadership is far more complicated than it may seem.