Appointed in 2010 by then-President Dmitry Medvedev and rubber-stamped by the Moscow City Duma, Sobyanin could have remained in office until 2015. Likewise, the Kremlin could have easily rolled back its plans to reintroduce direct popular mayoral elections in the capital and reappointed him.
But the Kremlin has clearly decided that, given the volatile political situation, Sobyanin needed a degree of popular legitimacy. Moreover, Sobyanin is popular among Muscovites and President Vladimir Putin trusts him to remain loyal.
"Political control of the situation in the capital is a priority for the Kremlin. And in terms of efficiency, it is logical for the presidential administration to support empowering the mayor," political analyst Tatyana Stanovaya wrote in Slon.ru.
And holding elections in September rather than in two years gives potentially strong opponents like billionaire oligarch Mikhail Prokhorov and anticorruption blogger Aleksei Navalny -- both of whom have expressed interest in running -- little time to prepare.
Moreover, Prokhorov, who has extensive foreign assets, would be hard pressed to repatriate them in time to be in compliance with new legislation restricting officials from such holdings. And as Stanovaya notes, "experience has shown that Prokhorov is not interested in a serious confrontation with the authorities" and would probably choose not to run anything but a symbolic "face-saving" campaign.
And Navalny remains tied up fighting fraud charges, widely viewed as politically motivated, in Kirov Oblast.
So at first glance, a Sobyanin "resignation" (and it’s not really a resignation because he will probably remain in office as "acting mayor") looks like a clever move. But then again, at the time so did the so-called "castling" of September 2011 when Putin and Medvedev pulled their job switcheroo -- inflaming public opinion and giving birth to the protest movement.
Similarly, the Kremlin's current strategy also carries serious risks.
The election in the capital will most likely be scheduled for September 8, the same day voters in the surrounding Moscow Oblast will go to the polls to choose a governor.
Former State Duma Deputy Gennady Gudkov, who says he plans to run for governor, said the Opposition Coordinating Council could nominate Navalny as its candidate for mayor. Such a unified opposition "ticket" could galvanize disaffected voters and prove to be a major headache for the authorities.
Moreover, it would make a guilty verdict in Navalny’s trial, or any additional legal action against Gudkov, look brazenly political.
And it's not as if the authorities can just rely on traditional "administrative methods" to get the result they want.
"In the new Russia, after December 2011, there is a new criteria for evaluating elections -- their honesty. The Kremlin will need to pay attention to this social demand that there be honesty and transparency of the campaign and in the vote count," Stanovaya wrote.
This is especially true in Moscow, which has the highest concentration of opposition-minded voters and who have become increasingly vigilant and creative in policing electoral abuses.
Of course there will be shenanigans, there always are. But the old tricks won’t work the way they once did.
And finally there are the parallels with the "castling" -- the sense that the authorities are playing loose and fancy with the rules, transparently moving the goalposts, and playing the voters for fools.
This has long been the default setting for the Kremlin. But Muscovites in particular are growing tired of this kind of virtual politics -- and their frustration could become manifest again in September.
Of course the Kremlin can pull this all off, and probably will. They can convict Navalny, which would bar him from the race. They can send a message to Prokhorov to stand down. They can get Sobyanin his popular mandate in the opposition-infested capital.
But like with the castling, it could also come at great cost.
-- Brian Whitmore