Nonviolent revolutions do not always remain nonviolent, as the examples of uprisings in Egypt, Libya and Syria in the Arab Spring have shown. But peaceful movements for regime change often do succeed. For example, they have toppled illegitimate rulers, as with the post-Soviet Color Revolutions in Georgia and Ukraine, and ended apartheid in South Africa. Before that, the peaceful civil rights movement in the United States ended the discriminatory Jim Crow system in the South. Nonviolent movements broke British rule in India and Malawi and brought down authoritarian regimes in Chile, the Philippines and Portugal.

On the surface, most of these cases seem so different from present-day Russia as to be irrelevant to the success or failure of the current protests against Prime Minister Vladimir Putin's rule and the protesters' call for free, fair and competitive elections. But which differences are important?

The immediate outcomes of nonviolent movements for political change are not decided by macrofactors such as levels of education, unemployment or the presence of a modern middle class. After all, civil resistance has succeeded in poor, backward countries, like India — and failed in rich, educated ones, like the Gulf states.

Nor do short-term windows of opportunity play a decisive role. No serious economic crisis was needed for Chileans to oust General Augusto Pinochet, while Panama's Manuel Noriega survived a massive nonviolent protest movement, despite crippling economic problems and divisions within the ruling elite.

Recent research by the sociologists Erica Chenoweth, Maria Stephan, and Sharon Erickson Nepstad shows that one factor more than any other determines whether nonviolent struggles succeed: protesters' decision to adopt nonviolence itself. Indeed, Chenoweth and Stephan have shown that peaceful protests are more than twice as likely as violent confrontation to bring about complete or partial regime change.

But the outcome of civil resistance also depends on the precise methods used. Challenging the regime's legitimacy and withholding skills and material resources from it are important, as is creating free spaces for dissent and maintaining the movement's unity and clarity of purpose. Most important, as Nepstad has shown, a protest movement aimed at regime change needs to win over critical parts of the police and armed forces.

Conversely, a government that secures the unconditional loyalty of its troops will be able to crush even the most sustained popular protests. Yet it can do so only at the cost of much bloodshed, and a half-hearted or ineffectual crackdown makes the protesters' triumph much more likely.

Given this, what are the prospects for Russia's current protest movement? So far, it has gotten many things right. It has focused on a single demand: fair elections. In addition, it has united liberals, Communists, nationalists and otherwise apolitical citizens in a broad coalition, despite these groups' mutual disdain and a colossal potential for rifts.

Like the 2000 Serbian uprising against Slobodan Milosevic, the Russian movement has produced an astonishing upsurge in grassroots creativity and political wit. A good example is the recent "nanoprotest" in the Siberian city of Barnaul, where police officers were forced to write up a report on a group of Lego figures brandishing slogans. These toy protests have now spread to other cities.

To circumvent biased reporting on state television and bridge the huge distances between Russian cities, the protesters have used decentralized means of communication such as social networks. There are more than 50 million Internet users in the country, and high-speed Internet connections have penetrated even remote corners of Russia in recent years. What's more, blogging services such as LiveJournal have been prominent for a decade. Thus, the Internet plays a more important role than it did in Iran's abortive Green Revolution or during the Arab Spring.

Nonetheless, Russia's size could become a liability for the protesters if things come to a head and, say, Putin refuses to accept a defeat in the March election. While there have been regular protests in cities from Stravropol in the south to Khabarovsk in the Far East, only Moscow and St. Petersburg have seen true mass demonstrations. As in Serbia in 2000 or Ukraine in 2004, where demonstrations played out mainly in the capital cities, Russia's metropolises have long been hotbeds of dissent. Unlike Serbia and Ukraine, however, provincial protesters would be unable to come to the rescue in case of a showdown.

In the Philippines in 1986, President Ferdinand Marcos' tanks were stopped by nuns and small children. In the fall of 1989, East German soldiers joined their fellow citizens in the protests that brought down the Berlin Wall. But during the same year in China, protesters in Beijing were crushed by troops from Inner Mongolia who didn't understand Mandarin and had no sympathy for big-city dwellers.

While army units or riot-control forces, such as the OMON, stationed in Moscow are too disgruntled by the recent police and military reforms to participate in a bloody clampdown, special-

operations forces from the provinces, staffed with veterans of the Chechen war, might cherish the excitement of sticking it to the Moscow fat cats. Likewise, army officers from poorer regions are more grateful for the kinds of salary hikes that Putin's United Russia party announced with so much fanfare shortly before the recent State Duma elections.

But while some parts of the security apparatus might support an initial crackdown, violent repression would be difficult to sustain. That means Putin would be well advised to heed the protesters' demands and hold new and fair parliamentary elections. If he opts for violent confrontation, the short-term outcome will be decided by the loyalty of the armed forces. His long-term fate, however, would be much grimmer.