Natural selection of an intellectual aristocrasy.

British universities are considering trying out a version of America's standardized admissions test - the SAT. Supporters of the idea hope that the SATs focus on basic reasoning skills in maths and English, rather than knowledge of specific subjects, will unearth some rough diamonds who have not I benefited from coddling at exclusive schools. Britain's interest is ironic, considering that this half-century-old multiple-choice exam is under assault in the US for being exclusive. The charge is true in the sense that the IQ-based test is one of the keys to admission at colleges for which there is fierce competition for places. Every year thousands of 18-year-olds must face the fact that they cannot attend Princeton or Harvard because they have failed to score. Anxious parents routinely pay many hundreds of dollars to private tutors in an attempt to boost their offsprings' SAT scores.

The latest blow against the exam has been struck by Richard Atkinson, president of the giant University of California system. Mr Atkinson says the test discriminates against minorities and converts the admissions process into the "educational equivalent of a nuclear arms race". Other colleges are also talking of dropping the SAT exam in favor of more malleable educational criteria.

This is a classic case of slaying the messenger. The SAT is not perfect. But compared to the other things on offer, it emerges as a veritable gold standard of objective testing. What, after all, can be wrong with a test that monitors abilities to read reason and calculate? Over the decades the SAT has served as a great democratizing force.

Consider the SAT's record. Back in the 1930s, America's Ivy League colleges really were discriminatory. Middling Wasp pupils at Groton or other prep schools assumed entrance to Harvard was birthright. Meanwhile, Brooklyn immigrants of higher intelligence contented themselves with four years all New York's City College. Blacks stood almost no chance of scaling the Ivy League towers.

Then James Bryant Conant, Harvard's president, mounted a revolution. He introduced an admissions test that examined intelligence rather than preparation. As the author Nicholas Lemann recalls in a history of the SAT, his inspiration was Thomas Jefferson who had written that merit must be allowed to flourish: "There is a natural aristocracy among men. The grounds of this are virtue and talents. There is also an artificial aristocracy based on wealth and birth." Harvard implemented a forerunner of today's SAT and others soon followed.

The doors opened. For the first time poor Italians, Jews, Irish and other minorities won admission in large numbers at top colleges. Women, long shut out of the Ivy League, performed so successfully on the SAT that they came to make up about 50 per cent of the students. Many blacks and Hispanics also gained entrance because of their high scores. The shift demonstrated it was possible to pursue the Jeffersonian democratic ideal of education for all.

The trouble was that the results of this pursuit were not always politically palatable. While individual blacks and Hispanics scored highly, these groups in aggregate scored less well than other groups. Universities decided to downplay the SAT in evaluating these black or Hispanic candidates, instituting the controversial quota system known as affirmative action. The SAT still found itself under attack, both for the score disparity among groups and other pretexts.

The fact that striving families scraped together cash for SAT cramming courses also fuelled the campaign against the test. This was despite the fact that the effect of cramming was limited by the IQ-test-like nature of the SAT; no matter how much you prepare for an IQ test you cannot boost your score to the degree you could for a test on a matter of knowledge such as geography or history.

California offers the most gratuitous example to date of blaming the SAT messenger. Mr Atkinson has said that the test is bad for minorities. But the real reason there is hostility to the SAT in California is not that minorities have done poorly. It is that one minority - Asian immigrants - have done too well.

The SAT is said to have hindered Hispanics, who have not won places proportionate to their share of the population. But it is easier for officials to attack the SAT than to admit that their own old policy of bilingual education, which forced children to spendyears learning in Spanish virtually guaranteed mediocre performance on the English portion of the SAT. Blacks also seem to falling short in the California college contest' but then so are whites.

None of this deters Sat reformers, who continue to insist the test is “anti-minority” or “too stressful” – as if educational competition can ever be unstressful. The escalating crusade against the SAT raises the question whether the test can have a future in the US or the UK. Britain is just as preoccupied with equality of outcome as the US. Ant to the equity-obsessed, a measure that acknowledges some are more able than others is intolerable.