Even as Iranians Rise Up, Protests Worldwide Are Failing at Record Rates

Iran’s widening protests, though challenging that country’s government forcefully and in rising numbers, may also embody a global trend that does not augur well for the Iranian movement.

Mass protests like the ones in Iran, whose participants have cited economic hardships, political repression and corruption, were once considered such a powerful force that even the strongest autocrat might not survive their rise. But their odds of success have plummeted worldwide, research finds.

Such movements are today more likely to fail than they were at any other point since at least the 1930s, according...