Vladimir Putin's unforgiving brand of vendetta politics today claimed another prominent victim with the guilty verdict against Mikhail Khodorkovsky, the former oil magnate who dared oppose the Kremlin strongman.

There was never going to be any other result. In modern-day Russia, challenging Putin is like standing in front of a tank. Either get out of the way or expect – sooner or later – to be flattened.

Whatever else he is, Putin is implacable, relentless and unpitying when dealing with perceived enemies. In this, he follows a long-established Russian leadership tradition, and the public seems to like it, affording him approval ratings of 70% or above.

But the lengths (and depths) to which the former KGB spy appears ready to go have fuelled claims, such as those publicised by WikiLeaks, that Russia has become a corrupt "mafia state" under his tutelage.

An early example of the vendetta as a policy tool came in 1999 when Putin, then a largely unknown appointee of President Boris Yeltsin, took down Yuri Skuratov, Russia's powerful prosecutor-general.

Putin and the then interior minister, Sergei Stepashin, held a press conference to discuss a video, aired on state-controlled television, in which a naked man similar in appearance to Skuratov was shown cavorting with two young women.

Putin said the women were prostitutes engaged in an orgy paid for by criminals.

Skuratov's real offence appears to be that he had begun a high-profile corruption investigation involving Yeltsin and his inner circle, of which Putin was a part. He hit back after the exposé, accusing Putin of personally shielding corrupt Kremlin aides.

But the following year, with Putin by now installed as the president-elect, Russia's parliament decided (with only 10 votes against) to sack Skuratov at Putin's express request. Like Khodorkovsky, he was finished.

Putin's ruthlessness was seen again and again as he cemented his grip on power in the years following Yeltsin's departure.

Opposition parties were crushed under the juggernaut of United Russia, Putin's home-made political platform. Able politicians such as Mikhail Kasyanov, who he appointed prime minister, were discarded for showing too much independence.

Unbiddable former patrons like the oligarch Boris Berezovsky, now in exile in London, became personae non grata.

Even after more than a decade in power as the president and prime minister, Putin remains unbending. Speaking this month, he accused the opposition figures Boris Nemtsov, Vladimir Milov and Vladimir Ryzhkov of seeking power in order "to line their pockets".

He went on: "I think that if we allow them to do this … they'll sell out all of Russia."

Swallowing thoughts about pots and kettles, the three men vowed to sue him for "moral damages" – though much good may it do them, given the state of Russia's justice system.

In 2006 Anna Politkovskaya, a renowned journalist and human rights activist who opposed Putin's policies in Chechnya, was assassinated. Despite a state investigation, her murder remains unexplained. Others have suffered a similar fate, at home and abroad.

Seen up close in Helsinki earlier this year, Putin did not look the ogre his critics sometimes make him out to be. A physically small man who compensates by working out and pursuing outdoor sports, he appeared by turns arrogant, insecure, angry and resentful. It could explain his aggression towards those who criticise him.

Whatever the reasons, he has frequently exported personal animus into the foreign arena, too. The 2008 Russian invasion of Georgia followed a long, vindictive dispute between Putin and the Georgian president, Mikhail Saakashvili.

Much the same poisonous dynamic applied in Putin's dealing with Ukraine's former Orange Revolution leader, Viktor Yushchenko.

On issues such as European missile defence, Kosovo's independence and the row with Britain over Alexander Litvinenko's murder in London in 2006, Putin often appeared to take things personally – and rather badly at that.

In other cases, he would co-opt rather than confront, as he has managed to do with weaker individuals such as Germany's former chancellor Gerhard Schröder and Italy's PM Silvio Berlsuconi.

By refusing to back down, Khodorkovsky has become the latest in a long line of opponents to fall foul of Putin's vendetta politics. It is likely that he will not be the last.