It's a revolting spectacle: the two presidential candidates engaged in a frantic and demeaning scramble for money. By 6 November, Barack Obama and Mitt Romney will each have raised more than $1bn. Other groups have already spent a further billion. Every election costs more than the one before; every election, as a result, drags the United States deeper into cronyism and corruption. Is it conceivable, for instance, that Romney, whose top five donors are all Wall Street banks, would put the financial sector back in its cage? Or that Obama, who has received $700,000 from both Microsoft and Google, would challenge their monopolistic powers? Or, in the Senate, that the leading climate change denier James Inhofe, whose biggest donors are fossil fuel companies, could change his views, even when confronted by an overwhelming weight of evidence? The US feeding frenzy shows how the safeguards and structures of a nominal democracy can remain in place while the system they define mutates into plutocracy. Despite perpetual attempts to reform it, US campaign finance is now more corrupt and corrupting than it has been for decades. It is hard to see how it can be redeemed. If the corporate cronies and billionaires' bootlickers who currently hold office were to vote to change the system, they'd commit political suicide. We should see this system as a ghastly warning of what happens if a nation fails to purge the big money from politics.