Last week, Alexei Navalny, the recently convicted Russian opposition blogger, lawyer and candidate for the post of mayor of Moscow, posted a provocative item on his site.

It was an open letter addressed to the present mayor of Moscow, Sergei Sobyanin, accusing him of authorizing the theft of pro-Navalny banners from the city's municipal high rises. "Could you please answer my question?" asked Navalny, 37, tartly. "Why do you, along with your migrant workers for municipal utilities, steal our Navalny banners from the balconies of the residents who have installed them?"

As a statement, it was instructive in more than one respect. It illuminated the confrontational style that has characterized Navalny's rapid rise as one of Russia's most visible opponents of President Vladimir Putin and his inner circle. But also, in the reference to "migrants," it suggested why some harbor deep suspicions about Navalny's liberal credentials. Beyond all that is the very fact of Navalny, who was sentenced last month to five years in jail on the trumped-up charge of "stealing" a forest in Kirov region, of being free at all and able to run against Sobyanin.