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 authorising 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 characterised Navalny's rapid rise as one of Russia's most visible opponents of Vladimir Putin and his inner circle.
But also, in the reference to "migrants", it suggested why some harbour deep suspicions about Navalny's liberal credentials. Beyond all that is the very fact of Navalny, who was sentenced last month to five years' jail on the trumped-up charge of "stealing" a forest in Kirov region, of being free at all and able to run against Sobyanin.
On that last, puzzling point, theories abound, some conspiratorial and some grubbily pragmatic. The corruption sentence, against which Navalny is appealing, would ban him from holding public office if upheld. His chances of beating Sobyanin, in any case, look remote, according to opinion polls.
One plausible theory is that Navalny was released on bail at the prosecution's request - and for that read, with the Kremlin's approval - because Sobyanin, having called a snap election for one of the most high-profile public offices outside of the presidency, required a credible opposition foil to claim a veneer of legitimacy.