In the race to say something stupid about the tragedy in Haiti, the competition has been fierce. A proud British entry, John Sentamu, the Archbishop of York, spent a full five minutes yesterday waffling on the Today Programme in response to an increasingly bewildered John Humphrys asking him how he reconciled belief in a loving God with the devastation. Then another man of the cloth, US Christian fundamentalist preacher Pat Robertson, weighed in with a history lesson: back in the 19th century, the Haitian people "got together and swore a pact to the devil. They said, we will serve you if you'll get us free from the French. True story. And so, the devil said, OK it's a deal."

And while it is easy, and even necessary, for the sake of sanity, to remind ourselves that Pat Robertson is a deluded old man who also thought that the attacks on the World Trade Centre were divine retribution for the legalisation of abortion and gay marriage, and that Hurricane Katrina was just God's way of evening up the score after too much bonne temps roulez on Bourbon Street, the same can't be said of the most promising entrant so far in this dismal race to the bottom. Rush Limbaugh may be a recovering painkiller addict, but he's also the chief ideologue of the Republican party in the US. With his fellow shock-jock Glenn Beck, Limbaugh has waged a fierce and largely successful campaign to drive the few remaining moderates out of the party. So when he says that Americans should feel no need to contribute to Haitian Earthquake relief, since "We've already donated to Haiti. It's called the US income tax," it matters.

Limbaugh has his own pathology, and you don't have to be Sigmund Freud to think that a man in whose luggage DEA agents found a bottle of Viagra on his way back from a trip to the Dominican Republic might have picked another way to express his disdain for the Haitian people than by observing last year: "Haiti? You can't even pick up a prostitute down there without genuine fear of Aids." But crude racism – the same crude racism that scotched Limbaugh's plans to buy the St Louis Rams football team – is only part of what's going on here.

It's true that a certain kind of white person will never forgive the Haitians for freeing themselves from the French – just as another kind of person, white or black, will recall that same glorious history as one of the reasons not to write off Haiti or the Haitians. (And if you have any interest in the history, I urge you to read CLR James's great The Black Jacobins, published more than 50 years ago and still one of the best books about Haiti ever written.) But it's also a sign of how crazed the American right has become that Limbaugh could claim the Haitian earthquake was "made to order" for Obama because it would allow the president to "burnish his credibility … with both light-skinned and black-skinned" African Americans.

Now there are plenty of reasons to be disappointed with Obama – we write about them every week in the Nation. But you'd need more than a serious OxyContin habit to think Obama needs any burnishing among African Americans. No, what Rush is really doing is what he gets paid for: speaking aloud the things his millions of dittohead followers would love to say, but know they shouldn't. Will this make some Americans switch him off? It would be pretty to think so. Even prettier to think that millions more will be outraged enough to give to Haitian relief.

But you needn't remain a bystander in this fight. Limbaugh's employer, Premier Radio, is a subsidiary of Clear Channel, the largest provider of outdoor advertising in the UK. It would probably be unlawful to scribble "Shut Up Rush" on all their billboards, but you could certainly make your feelings known by telephone (+4420 7478 2200) to their offices at Golden Square – or via their corporate website.