"What is the most important right guaranteed by the US constitution?"

Like the Chicago River after the sewerage engineers got at it, the brain drain, I suspect, now flows in reverse. The collapse of the dollar makes it more likely that leading US academics will seek jobs in Europe than that intellectual migrants will continue to cross the Atlantic from East to West. I speak as one with shattered dreams of avarice.

But anyone who, in default of filthy lucre, feels tempted - by the promise of new experience or the excellence of American universities - to head for the US should beware a new hazard. Next year, the federal government will introduce a new examination for candidates for citizenship. I do not know why anyone would go to the trouble of seeking citizenship in the US. I find it costs so much in cash, time, energy and anguish just to apply for the right of residency that my spirit quails at the thought of pursuing a more elusive status. But I suppose the applicants include some of the most unfortunate immigrants: those whose own countries repudiate and persecute them, or whose best hope in life - Lord help them - is the American Dream. The blessings of life in America are available to anyone who can renew a visa and earn a green card - and you cannot get on to the citizenship ladder without first surmounting those obstacles.

The Tufts Daily , the student-run newspaper at the university where I work, has just challenged some of its readers to try a sampling of citizenship- test questions. They used the existing test, which is supposedly easier than the revised version approved for next year. On average, the students barely passed, even though most of them are US-born and bred, with years of study of US history and the American Constitution behind them. I tried the questions and scraped by with the minimum pass mark of 60 per cent. I see opportunities here for a new version of the game of Humiliation.

The trouble with the test is that anyone who thinks about the answers will get trapped in subtleties the bureaucrats never thought of. Faced with the question "What kind of government does the US have?" I immediately reflected on the questioners' agenda and felt the temptation to say "Democracy" or something equally tendentious. The only correct answer, according to the markscheme, is "a republic".

"What is the most important right guaranteed by the US constitution?" seemed a sly question, since it clearly calls for a judgment masquerading as a fact. I felt baffled. If the National Rifle Association wrote the question, the answer would be "the right to bear arms". Anyone brought up on cowboy movies would unhesitatingly plump for "the right to a fair trial" or "due process", as they now say - a right the Government, in defiance of the constitution, denies to terrorism suspects. The only "correct" answer is laughably dumb: the right to vote. Half the electorate in this country sensibly ignores this right, which amounts to the opportunity occasionally to mark a paper or dangle a chad for the gerrymanderers to despise. At the most, the right to vote enables those who exercise it to contribute to the alternation in office of Tweedledum and Tweedledee in a country where, as Gore Vidal once said, there are only two parties: conservative and reactionary.

I have been looking at sample questions for the new test. Some of them are nonsensical or, at best, misleading. Candidates are asked to "describe" amendments to the Constitution, but the markscheme demands definitions, not descriptions. Approved answers to the question "What are two ways that Americans can participate in their democracy?" relate only to party politics and public office, omitting the real greatness of US democracy, which people practise in workplaces, local communities and countless civic institutions. I calculate that you could give correct answers to all the historical questions and still fail the test. The markscheme allows mention only of political, economic or religious freedom in answer to the question "What is one reason colonists came to America?" In saying why colonists fought "the British", you would be marked wrong if you said to prolong slavery, or gain power for themselves, or avenge themselves on loyalist enemies, or obtain access to Native Americans' land, or even to avoid restrictions on the right to trade. When asked to name "one problem that led to the Civil War" you will score zero for mentioning the divergent cultures of North and South. The approved list of answers to the question that invites candidates to mention any of America's 20th-century wars excludes most of them. No question invites references to the Iraq War and the war in Afghanistan. Happily, "the War on Terror" does not count either. On reflection, I feel proud of my students' poor showing, and unashamed to admit my own.

Felipe Fernandez-Armesto is Prince of Asturias professor of history at Tufts University in the US.