The 3.5% rule is a concept in political science that states that when 3.5% of the population of a country protest nonviolentlyagainst a government, that government is likely to fall from power.

The rule was formulated by Erica Chenoweth in 2013. It arose out of insights originally published by political scientist Mark Lichbach in 1995 in his book The Rebel’s Dilemma: Economics, Cognition, and Society.

For example: 

• In 1986, millions of Filipinos took to the streets of Manila in peaceful protest and prayer in the People Power movement. The Marcos regime folded on the fourth day.
• In 2003, the people of Georgia ousted Eduard Shevardnadze through the bloodless Rose Revolution, in which protestors stormed the parliament building holding the flowers in their hands.
• In 2019, the presidents of Sudan and Algeria both announced they would step aside after decades in office, thanks to peaceful campaigns of resistance.

Here’s the research: 

Chenoweth and Maria Stephan studied the success rates of civil resistance efforts from 1900 to 2006, focusing on the major violent and nonviolent efforts to bring about regime change during that time. To be classified as successful, a movement had to achieve its aims within one year of peak turnout, and had to satisfy strict criteria for nonviolence. By comparing the success rates of 323 violent and nonviolent campaigns, Stephan and Chenoweth demonstrated that only 26% of violent revolutions were successful, whereas 53% of nonviolent campaigns were successful. Of the 25 largest movements they studied, 20 were nonviolent, and they found that nonviolent movements attracted four times as many participants on average than violent movements did. They also demonstrated that nonviolent movements tended to precede the development of more democratic regimes than did violent movements.

Chenoweth coined a rule about the level of participation necessary for a movement to succeed, calling it the “3.5% rule”, based on findings originally discussed by Mark Lichbach in 1995, in The Rebel’s Dilemma: Economics, Cognition, and Society. Lichbach proposed that 5% of the population could topple a government, and that no opposition movement could hope to ever surpass that number due to the free-rider problem.

In 2013, Chenoweth revisited Lichbach’s proposal using the Nonviolent and Violent Campaigns and Outcomes (NAVCO) 1.1 dataset. Chenoweth found that nearly every movement with active participation from at least 3.5% of the population succeeded.

All of the campaigns that achieved that threshold were nonviolent.

Chenoweth has cautioned that the rule should be viewed as a “rule of thumb” rather than as a hard-and-fast law. Chenoweth has noted that nonviolent campaigns attract participation from larger numbers of people than do violent ones, in part because they have fewer requirements for physical ability or weapons, and that the larger numbers of people result in a greater likelihood of gaining political success.

Subsequently, Chenoweth has noticed that both nonviolent and armed resistance have been decreasing in efficacy, concluding that this is the result of authoritarians learning from previous failures, coordinating with one another, and training their armies and police to discourage defections within their ranks. Consequently, Chenoweth has advised that civil resistance movements take these changes into account and alter their tactics accordingly.

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