Republican presidential hopeful Rick Santorum has been forced to distance himself from a key backer who suggested women should use aspirin as a means of birth control.

Rick santorum (Reuters)

Rick Santorum would like to talk about the economy: at a rally in Detroit on Thursday night he was trying to drum up blue collar votes in a bid to snatch victory in the state where his rival Mitt Romney grew up. But all the chat on the internet, at least, has been about sex, or the lack of it, at least: and it has forced Santorum to distance himself from one of his major financial backers.

The gals put it between their knees and it wasn't that costly. Foster Freiss

Former mutual fund boss Foster Freiss surprised everyone, not least MSNBC anchor Andrea Mitchell, when he strayed into the controversial debate over birth control. "Back in my days, they used Bayer aspirin for contraception. The gals put it between their knees and it wasn't that costly." he said. Freiss donated some $330,000 last year to the pro-Santorum group, The Red White and Blue Fund - and says he has given at least another quarter of a million bucks this year.

'Out of context'

Later he tried to laugh off the remark - insisting viewers had not "got the context" of his joke. Birth control pills, he said, had not been available in his day, so the idea of women using aspirin instead was pretty "silly" and "funny". Santorum himself defended Freiss, calling him a great philanthropist and a good man, who had "made a stupid joke" that "did not reflect on the campaign, or me." And he told the Buzzfeed website he was not responsible for every bad joke made by one of his supporters.

Moral stance

Except that Santorum's own views on contraception have also been in the spotlight - and appear far out of step with the vast majority of Americans. Santorum, a Catholic father of seven, is uncompromisingly opposed to birth control in all its forms. In an interview he gave back in 2006, he stated "I think it's harmful to women, I think it's harmful to society", and last year he told the evangelical Caffeinated Thoughts blog:"It's not OK. It's a licence to do things in the sexual realm that is counter to how things are supposed to be ...if it's not for purposes of procreation, then you diminish this very special bond between men and women."

I think it's harmful to women, I think it's harmful to society. Rick Santorum

Although Santorum wouldn't actually outlaw contraception if he became President, and has insisted it would still be freely available, he does believe that states should be free to ban it if they choose. He has pledged to end all federal funding for birth control, and in common with many Republicans, is vehemently against President Obama's plan to make religious institutions provide free contraception as part of their health insurance plans.

Political headache?

Most Americans, including a majority of Catholics, disagree, according to a New York Times/CBS News poll earlier this week which suggests there is widespread backing for the Obama proposal. And the Pew Research Centre found just 8 per cent of people thought contraception was morally wrong. Santorum's views are undoubtedly boosting his surge in the GOP primary campaign, especially among religious conservatives. But when it comes to the general electorate, it might prove a bit more of a political headache. And there is no magic aspirin cure for that one.

Felicity Spector writes on US politics for Channel 4 News.