With Russians taking to the streets to protest the recent flawed parliamentary elections, Prime Minister Vladimir Putin has suddenly ceased to be an inevitable leader. He may think that this spring he will be elected president — the job he held from 2000 to 2008 — and serve up to 12 more years in that office. But I, like many Russians, think the regime will fall before the March election or soon after.

As Putin’s grasp on the country loosens, I wonder: What would Russia look like today if he had never come to power? And now, what might be in store for a post-Putin Russia?

Twelve and a half years ago, then-President Boris Yeltsin plucked Putin as his successor from a tiny pool of bureaucrats who had remained loyal to him when his popularity plummeted. If Yeltsin had picked someone else, it almost certainly would have been another little-known functionary. This person would probably have been, like Putin, afflicted with severe nostalgia for the Soviet past — when the country was feared, the trains ran on time and most people did not like to stand out from the crowd. But this hypothetical bureaucrat’s love of all things Soviet would probably have been more obvious to the West than Putin’s has been.

One candidate Yeltsin considered was Nikolai Aksenenko, an aging transportation official who hardly would have charmed George W. Bush the way Putin did. (Bush, after all, said he could look into Putin’s eyes and glimpse his soul.) With someone like Aksenenko in charge, Bush would have noticed much sooner that Russia’s foreign policy was becoming hostile to the West in general and the United States in particular.

Nor would Aksenenko, happy with the status quo under Yeltsin, have been likely to undertake a massive campaign to redistribute the wealth in Russia, like Putin did, concentrating it in his and his cronies’ hands. And Aksenenko died in 2005, so he wouldn’t have had Putin’s staying power. These two factors — the concentration of wealth and political power, with the pervasive corruption that accompanies it, and the indefinite extension of the Putin era — are fueling the protests in Moscow and elsewhere.

The protesters have no unifying political belief or demand, except for new, transparent elections, the opposite of the rigged ones of Dec. 4. Putin and President Dmitry Medvedev so far seem resolved to ignore the demonstrations. Medvedev has dismissed allegations of election fraud, while Putin has mocked the protesters. But the protests are the largest Russia has seen in 20 years. Earlier this month, people demonstrated in about 100 cities and towns across the country.

Putin is laughing at his own peril: He is a leader on his way out. But when regime change occurs, organizing a truly democratic election in Russia will be a formidable task.

Over the past 12 years, Putin has built a system that keeps the opposition off the ballot and out of the media and the public eye. Russia will have to do the hard work of rebuilding media, reconstructing the electoral process, re-creating political institutions and inventing a political culture virtually from scratch.

Nationalism — the most primitive of political instincts, which loves a cultural vacuum — is a real danger. Young people demanding a “Russia for the Russians” may emerge as the strongest political force in the country. In that case, Russia’s anti-Western stance would become even more entrenched. That would not bode well for the future of U.S.-Russian ties or for potential cooperation between the two nations where the world needs it most: in the Middle East.