The guards who tortured Sergei Magnitsky at Moscow's Matrosskaya Tishina prison, and refused to allow doctors to treat the pancreatitis that eventually killed him did not understand that they had fashioned a weapon for democracies to wield against dictatorships.  Until that moment, on 16 November 2009, all the talk of globalisation had missed one obvious fact – the wealthy could indeed move their money across national borders in ways that were once unimaginable. However corrupt a communist was in the cold war, his wealth had to stay in the old Soviet Union or in China or eastern Europe. From 1991 on, oligarchs or red princelings could hide their money where they wanted.  But the options for those who robbed or murdered their own people were not limitless. They did not stash their loot in their own countries, as a rule. They feared revolutionaries taking power and taking back the stolen goods. They could direct wealth to Russia, the new capital of global reaction. But trusting the Putin regime and Russia's corrupt banking system and judiciary has never been wise. Instead, they wanted what oligarchs and the willing servants of dictatorial regimes have always wanted: a town house in Mayfair, an apartment in Manhattan or a villa on the Riviera, where they could be safe; and City, Swiss or Wall Street lawyers and bankers, who could protect their wealth. The democratic world was their bolt hole and pension plan.  On Thursday night, Ukrainian liberals and journalists reported that private jets were taking off from Ukraine as fears grew – and let us hope they are not groundless – that President Yanukovych and his death squads were entering their last days. The charter manifest at Kiev's Zhulyany airport on 20 February, said one, read like a Who's Who of Ukraine's richest men. Which way would they head – east or west? As far as Ukraine's planespotters could tell, they wanted to head west to countries with the rule of law and protections for private property, rather than east into the hands of the rapacious Putin and his officials.  Just like the families of Chinese communists, who store their wealth in the British Virgin Islands, when the moment of choice comes, they prefer financial security to ideological conformity. For instance, one of Ukraine's richest men has paid more than £100m for a luxury apartment in London. We should not be surprised if such men decide to delight us with their company if the old regime falls and its unreasonable replacement takes against them.  Bill Browder, the investment fund manager who had hired Sergei Magnitsky, has become one of the most important human rights innovators of our time because he understands money's limits. The Russian state murdered Magnitsky because he revealed how officials and gangsters had used Browder's investment funds to perpetrate a $230m (£138m) fraud. Browder lobbied with a polite determination that those of us who have come to admire him know not to underestimate. He collected evidence against officials complicit in the fraud and murder. He then began persuading western governments to deny visas to the men on his list and freeze their western assets.  The fury with which Moscow responded to the threat to its plunder ought to have alerted the world to the Magnitsky Act's potential. The authorities disinterred Sergei Magnitsky's corpse and put it on trial – a desecration of both the dead and the judicial process not even Joseph Stalin attempted. To be fair, French politicians and judges have learned the lesson. Understandably ashamed that their country provided a refuge for Jean-Claude "Baby Doc" Duvalier of Haiti and "Emperor" Jean-Bédel Bokassa of the Central African Republic, they have seized property belonging to Uzbekistan and Equatorial Guinea's ruling clans. .  Overall, western governments have shown little inclination to follow the money, however. Barack Obama has chartered his inability to stand up to Putin in his reaction to Magnitsky laws. The US Congress had to force him to impose sanctions against Russian officials in 2012. The administration ought to have supplied a new list of targets on 16 December last year. Nothing happened, because Obama and John Kerry did not wish to offend Putin before his games in Sochi.  In their desire to be polite, you can see the treacheries of the dominant strand of liberal-leftism of the last decade rebounding on others. Rather than just say they did not wish to repeat the foreign wars of the disastrous Bush administration, Obama and his many admirers convinced themselves that authoritarian threats were phantoms of the neoconservative imagination. If only they could ignore dissenters and "reset" relations with the Kremlin, Russian and western governments would snuggle up to each other as friends.  As Michael Weiss, of Institute of Modern Russia, pointed out last week, Moscow advises its allies to unleash "hell when the moment is right" and then present the bloody aftermath "as a warning of what happens if the status quo is not maintained". As I and many others have written, Putin wants to create a "conservative international" to unite the world's repressive governments and movements against liberalism. If Obama and his "progressives" can't oppose a united authoritarian front, the time has come for them to curl up into a ball and drop themselves into history's dustbin.  Not that the European Union has been much better. The European parliament is so annoyed at its failure to enforce Magnitsky sanctions that it is preparing to compel it to act. European governments, including Britain, only threatened sanctions against the organisers of murder in Kiev at the last minute when the time for effective threats had passed.  I am sure there are legal difficulties, although the French judiciary has said that the law does not protect stolen money. I am sure that diplomats in London and Washington are whispering warnings about dictatorships the west supports in Bahrain and Egypt. Against them lies the effectiveness of the best modern response to state terror.  "You complain about 'western imperialism'," we should say. "Allow us to show you what modern imperialism will do to you if you even think of sending snipers to shoot peaceful demonstrators. We will change the locks of your apartments on Fifth Avenue, the Avenue Montaigne and Kensington Palace Gardens. We will shutter your villas of Cap Ferrat. Then we will empty your bank accounts so completely you will realise that all your thieving has been for nothing."
Nick Cohen: The most effective method of hurting those who murder their own people is to recover the wealth they have amassed