Oligarchy and plutocracy are not necessarily incompatible, but they are uneasy bedfellows. Such is the lesson from Russia in recent days, following the arrest of Mr Mikhail Khodorkovsky, the country's richest businessman, on charges of fraud and tax evasion.
The move is seen as an initiative by the small group of securocrats surrounding President Vladimir Putin against the small group of fabulously wealthy business figures typified by Mr Khodorkovsky - and as a warning that they should not seek to become involved in politics. On the outcome of this struggle may hinge not only international confidence in Russian markets, which have fallen sharply on the news, but Russia's longer term political stability.
President Putin has backed the federal prosecutor's decision, saying "every one should be equal before the law". He also says there will be no mass revision of the privatisation sales in the 1990s under ex-President Yeltsin, which gave this small group of rich men such an opportunity to become a full-blooded plutocracy, especially in the oil and gas sectors they now dominate. The manner of Mr Khodorkovsky's arrest worries some presidential advisers nonetheless, with resignations pending.
Mr Putin is playing a canny game ahead of parliamentary elections in December and presidential ones next March. Mr Khodorkovsky has actively supported a number of liberal candidates and parties. He is widely believed to be laying the basis in the longer term for a political career himself, even as a presidential candidate in 2008. Although his entrepreneurial talent is admired, there is little love lost between the Russian public and the plutocracy he represents (or Putin's oligarchs). They are regarded as having creamed off public resources in an economy whose GDP is still only two-thirds of what it was in 1989. Much of this money was exported; it is only recently being returned on a large scale and contributed to an increased growth rate and higher employment.
The group around Mr Putin is drawn from former KGB, police and military groups, like himself, substantially unreformed since the end of the communist period. Phrases such as "totalitarian capitalism", "KGB-isation of the state" and "capitalism with Stalin's face" are being used by commentators to characterise the emerging system, in which basic civil liberties, political organisations and media freedoms are widely circumscribed and a pervasive cynicism exists about the public sphere. The one thing the group around President Putin fears is political competition from the plutocrats. How this affair plays out will affect not only the Russian government's domestic legitimacy but its international credibility.