As the largest protest since the fall of the Soviet Union erupted in Moscow, political activist, renowned blogger and Yale World Fellow Alexei Navalny sat in a jail cell, unable to see the whirlwind of political activity that now surrounds him.

Navalny was arrested for obstructing traffic during a protest on Dec. 5 and sentenced to 15 days in jail, the longest possible sentence for the crime. Since then, he has become the face of Russian protests accusing United Russia, the incumbent party of Russian President Dmitry Medvedev and Prime Minister Vladimir Putin, of rigging elections.

Six days after Navalny’s incarceration, 50,000 peaceful protesters marched in Russia, many carrying signs with Navalny’s popular slogan calling United Russia “the party of crooks and thieves.” Though only 7 percent of Russians recognize Navalny, two-thirds of Russians now recognize his slogan, according to the Economist.

A letter Navalny wrote from his jail cell was published on his website and read to the crowd at the protest. [See a translated version here.]

“It’s impossible to beat and arrest hundreds of thousands, millions,” the letter read. “We are not cattle or slaves. We have voices and votes, and we have the power to uphold them.”

In an interview from his jail cell, Navalny told the Russian newspaper the New Times that he was happy to see such large protests, but added that there was still work to be done.

“I am very grateful to those people who come to picket with slogans like ‘Free Navalny,’ ‘Free Yashin,’ but these slogans have to be changed,” Navalny said. “’Freedom for all political prisoners!’”

While Navalny may try to deflect attention from himself, he is quickly becoming a major Russian political figure. Two days after Navalny’s arrest, Medvedev’s Twitter account retweeted a vulgar attack making a direct reference to Navalny.

“Today it became clear that a person who writes in their blog the words ‘party of crooks and thieves’ is a stupid, c——-ing sheep :),” said the tweet, originally written by Konstantin Rykov, a Russian politician.

The Kremlin quickly removed the tweet and said that the account had been hacked by an employee in charge of technical support for the account. A press release promised that “the guilty will be punished.”

International press have noticed the flurry of activity surrounding Navalny. Major news organizations have profiled him, including the New Yorker, the BBC and the New York Times. Nine days after his incarceration, Time Magazine covered Navalny, among others, for its 2011 Person of the Year article honoring “The Protester.”

Several news organizations, including the BBC, have speculated that Navalny might be able to challenge Putin for the Russian presidency in 2012. Before his arrest, the Moscow Times ran an opinion piece with the title “The Only Electable Russian is Alexei Navalny” which claimed that “as of today, not a single Russian public figure other than Navalny has any chance at all.”

According to Russian radio station Ekho Moskvy, the Russian United Democratic Party “Yabloko,” an opposition party to Putin’s United Russia, has proposed nominating Navalny for the presidency.

Putin has declared his intent to run for president, and when the New Times asked Navalny about a potential candidacy, he declined to comment.

“I think that to give an answer to this question at this point and in the context of all that is happening is stupid,” he said. “That should not be discussed here.”

Navalny is scheduled to be released on Dec 20. A major protest is scheduled for Dec. 24.