[Stephen Howe is Tutor in Politics at Ruskin College, Oxford.]

The opening minutes of the Russell Crowe film Gladiator depict a dramatic confrontation between the armies of imperial Rome and the wild German tribes who resist them. The Germans reject the Roman demand for submission in fairly forthright style – by sending the emissary back to the legions’ lines, still mounted but headless. As the gory figure gallops into view and the barbarians roar defiance, one of Crowe’s legionary sidekicks says simply: “People should know when they’re conquered.”

It’s a scene, a line, and an assertion that could be used as a starting-point for classroom discussion on any and every aspect of the history of empires. “’People should know when they’re conquered’ – discuss, with reference to ancient Rome, medieval Ireland, Victorian Maori or Zulu, 21st century Iraqis…”

In the media, a great deal of current debate about Iraq or Afghanistan pivots around the question: when should people recognise that they have been conquered – or liberated? In academia, a large proportion of recent historical work on past British and other empires focuses on related issues: when did people recognise that they were conquered? How did they react, adapt, cooperate or resist? How did they think about those who had conquered them – and how were their ideas about themselves reshaped by the fact of conquest?

Meanwhile, behind these debates and researches lies a parallel assertion about modern global politics and its antecedents, less often explicitly posed but only a little less central to current debates among analysts, current affairs polemicists or indeed historians: “people should know when they are conquerors.”

This would-be teachers’ aid also carries its associated questions. How should United States – or British – citizens today react to being (or being perceived as) hegemons, imperialists or aggressors? What stories do they tell themselves about their countries’ global roles? How do these relate to their conceptions of national and other identities? How far or in what ways have notions of themselves as “being imperial” entered into, or even constructed, such identities?

Niall Ferguson’s worldview revolves almost entirely around those two assertions. Some people – mostly poor and dark-skinned ones – need to recognise that they are conquered, accept the fact, indeed realise that it’s in their own best interests to be so. And other people, especially Americans, must know and accept that they are conquerors and imperialists, shoulder the accompanying burdens, understand that such a role benefits everyone.

As Ferguson says in the introduction to his latest book, Colossus (2004): “Unlike most of the previous writers who have remarked on this, I have no objection in principle to an American empire. Indeed, a part of my argument is that many parts of the world would benefit from a period of American rule.”

A portrait of the gladiator

At only just over 40 years old, Niall Ferguson has been named as one of Britain’s 100 most important public intellectuals by Prospect magazine, and even more notably, as one of the world's 100 most influential people by Time. After a glittering undergraduate and postgraduate career at Oxford University and several years teaching there, he soon achieved a repertory of prestigious posts worthy of some particularly well-connected medieval bishop.

For a time, he was simultaneously professor of political and financial history in Oxford, professor of economics at New York University, and senior fellow of the Hoover institution at Stanford. New York became his main base at the start of 2003, and in summer 2004 he is taking up a history professorship at Harvard.

Within weeks of arriving in the United States, Ferguson also found himself shuttling to Washington on government invitation, fraternising with policymakers from Colin Powell downwards. His existing profile as a pugnacious reviewer, columnist and TV pundit in London newspapers and on the BBC was rapidly complemented by the appearance of comparable ubiquity in the US news media....