By staging significant protest actions in almost 100 Russian cities Sunday, Alexei Navalny has laid down a serious challenge to Vladimir Putin.

The anti-corruption blogger-turned-politician wants to run for president in elections that are barely a year off, and has been conducting himself as if his campaign were already under way. The Kremlin has the means to prevent him, by invoking a criminal conviction, recently upheld by a regional court, that could bar him from running for office.

It has been standard procedure under Mr. Putin's brand of "managed democracy" to cull the ballot, using various pretexts, to ensure that independent challengers are kept out and results are tailored to match the authorities' expectations. That system has mostly worked in the Putin era, though it experienced a tough shock when tens of thousands of people took to the streets to protest alleged fraud in the 2011 Duma (parliament) elections. To continue working, the system requires public acceptance of election results, or at least apathy.

Until now, the overwhelming public perception has been that there is no alternative to Putin, no worthy challenger. Thus his return to the Kremlin next year – should he wish it – has seemed inevitable.

But the size and scope of the nationwide wave of protests may have just upended that view, analysts say, by demonstrating that Mr. Navalny is a serious contender, and that his signature issue of corruption in high places can bring tens of thousands of mostly youthful Russians onto the streets, despite the very real threat of arrest.

"This changes the whole political outlook," says Dmitry Oreshkin, head of the Mercator Group, a Moscow media consultancy. "A new generation has become politically active, mostly people under 25 who recently became voters. Before this, they actually ignored protests. But Navalny found a language to address them with. It's not the old denunciations of 'Putin's bloody regime,' but just the calm demand for genuine investigations of corruption at the top, or else everyone will understand that the authorities tolerate corruption."

'Now it's Putin or Navalny'

Sunday's march by at least 10,000 protesters was the biggest such demonstration in Moscow in five years. Police detained around 1,000 of them. A Moscow court sentenced Navalny on Monday to 15 days in prison for organizing an unsanctioned rally and "resisting arrest" – a familiar routine for him by now, and one he used to send out defiant tweets to his followers. Kremlin spokesman Dmitry Peskov described the protests as "a provocation and a lie," and suggested Navalny's young supporters may have been paid to turn out.

The challenge facing the Kremlin now is to either permit Navalny to run against Putin next year, or prohibit him and risk alienating his substantial youthful base and perhaps igniting a fresh wave of protests. No one thinks Putin, one of the most successful leaders in Russian history whose public approval rating hovers around 80 percent, is likely to lose that contest. But Navalny might do surprisingly well. In 2013, he was allowed to run for mayor of Moscow against Kremlin stalwart Sergei Sobyanin, and he stunned the establishment by winning 27 percent of the votes.

Polls show that Navalny has been steadily gaining in name recognition, though more than half of Russians in a February poll by the independent Levada Center still said they hadn't heard of him. Only 1 percent indicated they would vote for him in that poll, a decline in his support from 5 percent in 2011. Still, that could change if the Kremlin fails to manage his challenge wisely.

Navalny has gained a lot of traction with his charges of corruption at the top. A video prepared by his Anti-Corruption Foundation accusing prime minister and former president Dmitry Medvedev of massive corruption has garnered more than 11 million views.

There are no solid statistics on how great a drain corruption is on the Russian economy, but the perception of pervasive graft in high places is nearly universal among Russians. "We don't have any recent studies, but the problem of corruption is definitely not diminishing," says Georgi Satarov, a former Kremlin aide who heads the independent InDem Foundation in Moscow.

Unlike Russia's old-line liberal opposition, Navalny is not associated with the disastrous decade of the 1990s, and he is more in tune with the current nationalistic mood of Russians, which makes it difficult for the Kremlin to peg him as a pro-Western "fifth columnist."

Get the Monitor Stories you care about delivered to your inbox. By signing up, you agree to our Privacy Policy

"Navalny is acting the way a real opposition leader should," says Alexei Kondaurov, a member of the semi-official Council for Foreign and Defense Policy. "His film about Medvedev is directed not so much against Medvedev, who is an unworthy figure, but clearly against Putin."

Mr. Oreshkin says Navalny is now, officially, a danger to the Kremlin. "He's broken the authorities' scheme for the next election: Putin or nothing," he says. "Now it's Putin or Navalny."