In March 1793 the Girondin deputy Pierre Vergniaud warned the French Convention that the revolution, like the god Saturn in the old myth, might devour its own children one after another. Seven months later he and his fellow Girondins went to the guillotine. The phrase, credited to the Girondin deputy Pierre Vergniaud, has stuck because the pattern has recurred so often: revolutionaries who survive the old regime are killed or exiled by their own allies. Why does this happen?

No agreed rules, and fear of the first strike

When an old regime falls, the rules for settling disputes fall with it. There is no trusted court, no accepted constitution and no army that everyone believes is neutral. In that vacuum each faction fears the others will seize the state first. Political scientists call this a security dilemma: steps one group takes to protect itself look like preparations for attack to the others, so each has a reason to strike before it is struck. Former comrades become dangers simply because they are organized.

War and emergency

Revolutions frequently bring war, because neighbors fear contagion or see weakness, and exiles seek foreign help. In wartime, emergencies make dissent look like treason. Criticism of the government becomes aid to the enemy; special courts, censorship and suspended rights are justified as temporary measures. Defenders of the revolutionary governments have long stressed these circumstances, and they were real. But emergency powers have a way of outliving the emergency, and they are easily turned on rivals at home.

Outbidding and purity

In a revolutionary crowd, the person who calls for more usually sounds braver than the person who calls for less. This creates outbidding: radicals gaining by branding moderates as traitors. Each faction proves its loyalty by demanding harsher measures against the last group to fall, and yesterday's radicals become today's suspects. Robespierre's own fate shows how the spiral can consume even its drivers: the man who helped send Danton to the guillotine in April 1794 followed him there less than four months later. Ideology sharpens the spiral. If the goal is a perfect society, then almost any cost seems worth paying, and opponents stop being fellow citizens who disagree and become enemies of the people standing in the way of the future.

Arendt's comparison

The political theorist Hannah Arendt, in On Revolution (1963), compared the American and French cases and drew a provocative conclusion. The French Revolution, she argued, was overwhelmed by the social question of mass poverty. Faced with the desperate hunger of the Paris poor, revolutionaries made relief of suffering their aim and the people's will their standard, and urgent need crowded out the slower work of building institutions. The Americans, by contrast, could concentrate on founding freedom, and they produced lasting institutions that founded freedom: constitutions, divided powers and courts. The most serious criticism of Arendt is that she played down slavery in America. The young republic had an enormous social question; it hid it by excluding enslaved people from the political community altogether. Others note that America's lack of a feudal nobility and its abundant land did much of the work she credited to political wisdom.

Why devouring regimes can last

A grim irony runs through the record. Steven Levitsky and Lucan Way, in Revolution and Dictatorship (2022), found that regimes born of violent social revolutions, such as those in the Soviet Union, China, Cuba, Vietnam and Iran, have been unusually durable. Their explanation is that they fuse party and army and crush rival centers of power. The years of armed struggle produce a ruling party whose leaders and soldiers are bound together by shared danger, while the revolution destroys or captures independent churches, landlords, old armies and business elites that might later challenge it. Constant threats from counterrevolutionaries keep the ruling group united. So the same features that devour a revolution's children can keep its survivors in power for generations. Durability, in other words, is not the same as success.

Worked example: Iran after 1979

The Iranian Revolution began as a broad coalition. Liberal nationalists, leftist parties, students, bazaar merchants and clerics all opposed the Shah, who left the country in January 1979. Ayatollah Ruhollah Khomeini returned in February, and a provisional government under Mehdi Bazargan, a moderate engineer and veteran of the nationalist movement, took office. By May a new force, the Revolutionary Guards, had been created alongside the old army.

In November 1979 students seized the United States embassy, and Bazargan, unable to control events, resigned. Abolhassan Bani-Sadr was elected president in January 1980 but was impeached in June 1981 and fled to France. The leftist Mojahedin turned to armed attacks and were crushed in waves of executions; the communist Tudeh party, which had backed Khomeini, was dismantled in 1983. Meanwhile Iraq invaded in September 1980, and the war that followed helped justify emergency rule. Almost every mechanism appears: a vacuum, rival armed groups, war, outbidding in the name of purity, and a revolution that consumed most of its early allies while building a regime that has endured for decades.