You might think that US Republicans considering a run for the White House in 2012 would have piles of political and economic problems to focus on: home repossessions, job losses, petrol prices and the like. Why, then, are so many of them apparently obsessed with sharia, or "Islamic" law?

The former senator Rick Santorum, who announced his candidacy for the Republican presidential nomination on 6 June, has denounced "creeping sharia" in America. Another GOP presidential candidate, the former Speaker of the House of Representatives Newt Gingrich, has demanded "a federal law that says sharia law cannot be recognised by any court in the United States".

This isn't just right-wing rhetoric. A dozen US states are considering measures to ban sharia - which they define as the "legal-political-military doctrine" behind Islamist terrorism. But defenders of the various bills and proposals are unable to cite a single court case in which sharia has been invoked.

Take Oklahoma, which became the first state to make it illegal for its judges to rely on sharia in November 2010. Yet Muslims make up less than 1 per cent of the state's population - a minuscule 30,000 out of 3.7 million Oklahomans. The residents of the Sooner State are as likely to be judged according to Jedi law as they are by Islamic law.

Fearmongering

The hysteria around sharia has become the modern-day equivalent of the 1950s Red Scare, with Islamists replacing communists "under the bed" - on both sides of the Atlantic. First there was the focus on jihad and "holy war". Then the hijab and the niqab. And now, sharia. The very word sends chills down the spine of not just conservatives but liberals, too. It conjures up horrific associations of hand-chopping, flogging and stoning.

In the words of the Islamic scholar and Oxford academic Tariq Ramadan, "the idea of sharia calls up all the darkest images of Islam . . . It has reached the extent that many Muslim intellectuals do not dare even to refer to the concept for fear of frightening people or arousing suspicion of all their work by the mere mention of the word."

It isn't just Muslim intellectuals who have been pilloried for committing the cardinal sin of trying to have a calm and rational discussion about sharia. Take the Archbishop of Canterbury. Our esteemed guest editor might not thank for me raising the subject again (indeed, he might even be pulling at his non-Islamic beard as he reads the headline on this column), but in February 2008, ahead of a speech on Islamic law, Rowan Williams told the BBC that the adoption of some elements of sharia by the British legal system "seems unavoidable".

The political and media response was astonishing - frenzied, hyperbolic and Islamophobic. The Sun raised the spectre of "medieval punishments" being inflicted on the British public and claimed that the archbishop was "giving heart to Muslim terrorists plotting our destruction". Alison Ruoff, an obscure member of the Church of England's governing body, the General Synod, called on him to resign. Politicians, including the then prime minister, Gordon Brown, queued up to distance themselves from Williams's supposed gaffe.

The archbishop's nuanced yet thought-provoking speech in 2008 referred to a "real debate among Muslim scholars" over the meaning and scope of sharia and argued that "there is no single code that can be identified as 'the' sharia".

Most non-Muslims in the west seem united with hardline Islamists in the misguided belief that there is one monolithic, unchanging sharia. But Williams was right: there isn't. Sharia, which translates not as "Islamic law" or "religious code" but as "pathway to the water", extends beyond the realm of criminal and civil law and covers personal and ethical matters such as sexual relations, diet, hygiene, prayer, fasting and charity.

In the mainstream

There is no Muslim equivalent of the Ten Commandments codifying Islamic law. Nor does the Quran pretend to be an all-encompassing legal or penal code. Sharia, therefore, is constantly evolving, with different Islamic scholars - Sunni/Shia, conservative/liberal, Arab/ non-Arab - offering differing interpretations. Yet here in the UK, ahead of the government's publication of its updated strategy for tackling extremism and terrorism on 7 June, officials briefed friendly reporters that any "advocacy of sharia law" would be deemed a failure to “reflect mainstream British values" and seen as a sign of extremism.

It is absurd to describe those who express the slightest support for sharia, in any shape or form, as "extreme" or "un-British". Is Gordon Brown an Islamic extremist? When he was chancellor, Brown repeatedly urged the City to become the "gateway to Islamic finance" and encouraged the proliferation of sharia-compliant banking in the UK.

Then there are those practising and observant Muslims - moderate, integrated, non-violent - who would consider themselves to be adherents of sharia in an ethical or social sense. Are they extremists, too? Polls show that most British Muslims oppose the introduction of sharia in this country; the minority of those who do express support for Islamic law tend to be referring to the resolution of civil disputes. I have yet to come across any mainstream British Muslim group advocating the execution of Ryan Giggs.

So sharia isn't what many think it is. Nor is it coming to a courtroom near you. Tackling the crises in employment and housing should be the priority for legislators. It's time to lay the sharia bogeyman to rest.