Leading article: Arizona and the fears over immigration

Almost certainly Arizona's draconian new anti-immigration law – that permits police in the state to question anyone they believe may be an illegal immigrant, even when they are not suspected of committing a crime – will not survive the battery of court challenges already under way.

But even if the law is adjudged to be a violation of civil rights and an invitation to harassment and racial profiling, the issue at its core will not go away. Nor is it confined to the US, as the heated exchanges over immigration in Thursday's final election debate in Britain make plain.

President Obama has spoken out against the measure, and Hispanic groups are organising protest marches this weekend in cities across the country. The fact, however, is that the bill passed by Arizona – where an estimated 8 per cent of the population is there illegally, and where crime associated with this human trafficking from south of the border is rife – has the support of almost three-quarters of Americans.

In the election debate, Nick Clegg was assailed for advocating an "amnesty" for illegal immigrants. A similar idea (never described as such) was central to the immigration reform bill promoted by President George W Bush that foundered in Congress in 2007. Although Mr Obama and the Democratic leadership on Capitol Hill are trying to revive the measure, any attempt seems bound to meet a similar fate. The issue is simply too full of political minefields.

But Mr Clegg's basic point remains valid. Sooner or later, governments will have to adjust to the world as it is – a world in the US where swathes of the economy are kept going by illegal immigrants, some of whom have been in the country for decades – rather than the world as they would like it to be. Alas, as the controversies in both Britain and Arizona show, in hard economic times voters are less willing than ever to accept reality.