Any number of reasons have been put forward to explain why the Russian president, Dmitry Medvedev, sacked Yuri Luzhkov, the mayor of Moscow, last week. Some commentators have put it down to an interview Luzhkov gave to Rossijskaia Gazeta in early September, in which he challenged Medvedev from what was thought to be a pro-Putin position. Others say it’s because Luzhkov failed to cut short his holiday and return to Moscow when the city was engulfed in smoke from the summer’s wildfires. Still others say it’s because Medvedev wanted to show that he was serious in his struggle against corruption, for which Luzhkov was notorious. Many think that it’s so the Kremlin can establish control over Moscow’s corrupt electoral mechanisms before the 2011 national elections. Almost all speak about a redistribution of capital flows between Russia’s various power groups.

Almost nothing, however, is known for sure. The origins of the media campaign against Luzhkov that was launched in mid-September, for example, are hazy, to say the least: the campaign was probably ordered by the presidency, but, according to some sources, the idea came from people close to the prime minister, Vladimir Putin. And we don’t know whether or not Medvedev discussed his decision to sack Luzhkov with Putin. Under these circumstances, perhaps the best question to ask is ‘cui bono?’

So who benefits? During his time in office Medvedev has changed almost half of Russia’s governors and regional leaders, all of them well-rooted figures with strong followings among regional elites, though none as powerful as Luzhkov: they include the presidents of Tatarstan, Ingushetia and Bashkiria, and the governors of Stavropol, Sverdlovsk, Amur and Oryol regions. Some, like Luzhkov, and unlike their appointed successors, were among the last remaining elected governors. By getting rid of them, Medvedev may have simply been strengthening Putin’s ‘vertical of power’.

But the sacking of Luzhkov may mean something else. Almost 70 per cent of Russians believe that Medvedev has no independent power but is controlled by Putin and his entourage. Luzhkov’s dismissal suggests that the situation may not be that simple. Luzhkov’s relations with Putin were complicated, but in recent years he has been much closer to Putin than to Medvedev. Luzhkov’s original decision to stand up to Medvedev, and to go on holiday to Austria despite the unfolding media campaign against him, can only be explained by one fact: that he believed he had Putin’s support. Putin did not comment on the media campaign publicly, but on 21 September he sent Luzhkov a telegram, wishing him a happy birthday and praising his achievements ‘as a competent and experienced professional’.

In a recent interview with the liberal Novoie Vremia, Luzhkov connected his sacking to the 2012 presidential elections. A few days earlier his wife, Yelena Baturina, a powerful oligarch in Moscow’s construction industry, told the same publication: ‘There are people in the Kremlin,’ she said, ‘who are worried that in the run-up to the elections Moscow’s mayor may support the position of prime minister Putin, not president Medvedev.' Many commentators wrote then that if Medvedev did not dare to touch Luzhkov his chances in 2012 would be zero. Getting rid of him has therefore strengthened the president’s position, if only in public opinion. Putin’s remark that Medvedev had every legal right to fire Luzhkov according to the law that he, Putin, had initiated, looked like a weak attempt to show that he had more to do with sacking the mayor than in fact he did.

So, for now, Medvedev has scored. But this isn’t the end of his struggle. After all the allegations of corruption against Luzhkov that have been splashed onto the TV screen, failing to prosecute him would be a sign of real weakness, turning Medvedev’s victory into defeat. Prosecuting him, however, means disturbing the hornet’s nest of the corruption system in Moscow as a whole. And this is a task too tall for any leader in Russia, however powerful, let alone Medvedev.

Meanwhile, there is the question of the new mayor of Moscow: will it be someone close to Medvedev, or to Putin? It remains to be seen who will benefit in the long run from Luzhkov’s dimissal.