'The victim who fails tenure procedure may never know the charges. There is similar justice in Guantanamo'

One of the pleasures of academic life - at least, one of the potential pleasures - is civilised argument. You can - or you should - quarrel over the reading of evidence or the interpretation of data without anyone taking it personally. Yet odium theologicum is hard to avoid. There is always someone in every seminar who resents correction. Review pages bristle with barbs. Books become missiles in inter-study brawls. Honourable demurrals are mistaken for affronts. Malice infects debate. This is one of the nastiest vices in the world of universities because it tends to inhibit frankness and distract inquirers from the truth.

Although I love working in US universities, I have found some of the deepest hatreds there. Once, when I was a visiting professor in an otherwise delightful department, I gave a dinner party and innocently invited two colleagues who, it turned out, had not spoken to each other for 25 years. They first fell out over what I think is the commonest American cause of such conflicts: they had differed over an appointment, or a promotion, or an application for tenure.

In Britain, such issues are resolved in committees largely external to the department concerned. Department members cannot therefore blame each other for decisions they detest. No one is in the invidious position of outwardly opposing a colleague's protege or spouse or lover or whatever, or even of seeming to challenge a colleague's judgment. In the US, where democracy and subsidiarity are so revered that all such matters are decided by debates within departments, ill feeling is almost bound to arise.

Conflicts over tenure probably cause most agony. In Britain, though some of us endure cruelly protracted apprenticeships in temporary appointments, security from dismissal comes with the job. In the US, academics must contest tenure separately from appointment or promotion, in a gruelling, complex, hazardous and often deadly procedure, in which rivals and foes have privileged means of attack. Typically, the procedure is triggered when a professor is about six years into the job, or when someone is elected to a chair. When I won my chair, the talks I gave and the interviews I endured did not suffice: to enjoy tenure, I still had to submit to a parallel form of torture, while ten or 12 specialists in my field, whose identities I did not know, deliberated in secret and pronounced my sentence. In many universities, departments petition collectively on behalf of a colleague, but individuals can write to the deans in confidence with dissenting opinions. The victim who fails the procedure may never know the charges, or the accusers, or the grounds of sentence. In some ways, there is similar justice in Guantanamo or before an auto-da-fe. Every department has stories of enmities that originated in disputes over tenure.

The system usually seems to lead to the right decision. But it has four disadvantages: it enslaves young scholars, who have to curry favour with senior colleagues to ensure their support when tenure time arrives. It privileges ill-intentioned voices. It encourages scholars to abuse professional disagreements to do each other down. And it is open to a growing form of exploitation: ill-run universities employ untenured teachers so as to be free to sack them when they become redundant or ideologically inconvenient; other institutions, including some of the loftiest in the land, practise the old Cambridge technique of sacking most young academics after a few years' service, either to pollinate the world with their products or to save money by substituting entry-level cannon fodder. In the university where I work, administrators encourage staff to seek and obtain tenure, but not all institutions are that honourable.

Yet there are good reasons for keeping the tenure system, despite its elaborate, expensive and sometimes hostile features. The founding fathers of the American Association of University Professors devised tenure in 1915 so "that men of high gift and character should be drawn by an assurance of an honourable and secure position, and freedom to perform honestly and according to their consciences the distinctive and important function that the nature of the profession lays upon them". Rigorous review of academics'

suitability for these lofty responsibilities was essential to confer prestige on a profession poorly rated in terms of pay. Moreover, US universities need to demonstrate extreme fastidiousness in self-examination. Typically, they are self-regulating. There are no nationally enforced standards. In the huge independent sector, universities form circles to oversee each other's quality of teaching and research. So every test must be torture, every assessment elaborate, every scrutiny searching. To be seen to be done, justice must be untempered with mercy.

Occasional odium is part of the price we pay for unquestionable excellence.

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