European politicians are far too often and far too easily beguiled by the surface glamour of American elections. This year in one vitally important respect, however, Europeans should look across the ocean at the 2012 presidential contest and pledge never to allow anything like it to take root here.

The 2012 US presidential contest is the first to take place since the US supreme court's game-changing 2010 ruling in the Citizens United case, which was brought, revealingly, by a very well-funded rightwing group campaigning against Hillary Clinton's attempt to win the Democratic party nomination two years previously. The ruling, passed 5-4 by the court's conservative majority, blew away most of the pre-existing restrictions on independent spending for political purposes by business and the unions. By allowing corporates to make unlimited donations of this kind, the court gave birth to the so-called Super Pacs, which are turbocharged fundraising "political action committees" that support a candidate while remaining nominally independent of his or her campaign.

The arrival of Super Pacs has allowed corporate big money to take control of the electoral campaign process to an unprecedented degree. The ability of the uncharismatic and relatively moderate (in Republican party terms) Mitt Romney to exert an increasing stranglehold over his party's nomination race has many causes, but the sheer size of Mr Romney's Super Pac, Restore Our Future, is certainly a crucial one of them. By the end of 2011 ROF had raised more than $30m, mainly from hedge funds and private equity groups, to promote Mr Romney. That money is overwhelmingly spent in paid-for TV attack ads. In recent weeks, ROF has blanketed campaign-trail states such as Florida, Nevada and Arizona with negative propaganda against Newt Gingrich. It is increasingly arguable that Super Pacs are buying the Republican election.

Four years ago, Barack Obama raised a huge campaign war chest of his own, but insisted he did not want to be beholden to outside groups. This month, though, the president has begun signalling that he wants wealthy donors to contribute to Priorities USA Action, one of the leading Democratic Super Pacs. Mr Obama has done this simply because he risks being overwhelmed by hostile Super Pac spending if he does not. But it is a watershed step nevertheless, ensuring that the corporate donors whom he once talked of bringing to heel will now instead further tighten their grip on the election battle.

More than ever before, American politics in 2012 is politics for sale – to the biggest donors. European politics may be frustrating in many ways, but it is better off not going anywhere near this baleful American example.