Even if he's allowed on the ballot, 40-year-old Navalny would be a long-shot candidate in a political system dominated by President Vladimir Putin and his United Russia party. Navalny's supporters are largely young, educated middle-class Russians who are active on the internet and live in cities like Moscow, where the candidate got 27% of the vote in the 2013 mayoral election.
Most people in Russia get their news from pro-Kremlin state-controlled television. Just 47% of Russians know who Navalny is, and of those, 63% say they definitely would not vote for him, according to a February poll by the independent Levada Center.
Navalny has documented the corruption of the political elite and made a mark with his rhetorical flair, coining the phrase "party of crooks and thieves" to describe Putin's United Russia. He's also been accused of using ethnic slurs with colleagues, appeared at a Russian nationalist march, and made videos derogatory of migrant workers from Central Asia and the Caucasus.