In the 43 years since its founding, Iran’s Islamic Republic has overcome numerous internal and foreign policy challenges.

But the massive public protests that erupted across the country last month following the death of 22-year-old Mahsa Amini, who died in custody after the morality police arrested her for “improperly” wearing her hijab, pose a major threat to the regime. Iran is in the grip of what may be its most serious crisis.

When the Islamic Revolution toppled the pro-Western monarchy of Mohammad Reza Shah Pahlavi and installed Ayatollah Ruhollah Khomeini as the country’s Supreme Leader, Western observers doubted that a theocratic regime would last long. Some analysts argued that religious fundamentalists could not possibly have the necessary skills or experience to run a sophisticated country like Iran.