On the surface, Moscow has never looked more prosperous. High-end restaurants are full. Cyclists, strollers, and rollerbladers crowd Gorky Park. Newly built skyscrapers give the city a modern skyline, and streets are clogged with late-model Western cars. But there is a growing sense of unease. Against the background of plummeting oil prices and vast sums of money being urgently sent abroad, the capital is now the scene of feverish political activity. For the first time, Vladimir Putin’s system of one-man rule appears unstable. No one knows whether it can survive or, if it doesn’t, what will replace it.

After years when opposition demonstrations typically attracted no more than a few hundred, Moscow since December has witnessed at least six major demonstrations that have drawn crowds estimated at 50,000 to 100,000. Nothing like this has happened in Russia since the fall of the Soviet Union. The protesters openly refer to Putin as a “thief,” an explosive charge in a society where Putin is suspected of massive corruption but the accusation is typically not made publicly.

The country is now in a state of suspended animation. In a poll taken in December 2011, after the first demonstrations, by the Levada Center, a Moscow-based organization that conducts sociological research, 61 percent of Russians said they were sure that 2012 would not be a calm year and reported feelings of foreboding. This perception derives in part from a belief that the Putin regime will not leave the scene peacefully. According to Russian political analyst Lilya Shevtsova: “Relinquishing political control could mean not only loss of assets but also of freedom or even life. Lights burned late in the Kremlin during the Arab Spring and conclusions were drawn: Lose your grip on power and you end up like Hosni Mubarak or Muammar Qadhafi.”

The first event that led to the protests was Putin’s decision to run for a third term as president. It exposed the presidency of Dmitri Medvedev in 2008–12 as a sham. Despite his pledges to fight corruption and his denunciations of “legal nihilism,” Medvedev achieved only one thing during his tenure: He extended the president’s term in office to six years. When the parliamentary elections of December 4 were then blatantly falsified, Russians’ patience broke. Thousands took to the streets.

The Putin regime now faces an opposition that consists of three parts. (There are also permitted opposition parties, but these are controlled by the Kremlin.) The liberals include former deputy prime minister Boris Nemtsov, the anti-corruption blogger Alexei Navalny, and the youth leader Ilya Yashin. They call for honest elections and the freeing of political prisoners. The socialists are organized into an umbrella group, the Left Front, headed by Sergei Udaltsov, a former aide of the Communist-party leader Gennady Zyuganov. They call for preserving the “best of the Soviet Union” — free education and medicine, nationalization of big business, and domination of the former Soviet republics. The nationalists consist of a few public organizations and thousands of street thugs. They call for the domination of Russia by ethnic Russians and for the expulsion of Central Asian and Caucasian migrants.

Putin’s public attitude toward the protesters has been dismissive. He has said that their symbol, a white ribbon, resembles a condom. One of his aides has compared them to the White Brotherhood, a 1990s messianic sect in Russia and Ukraine that was responsible for a number of suicides.