Each statement suggests parallels between past and present and the contradictions of imperialism. Can the miseries of war be outweighed by the blessings of peace delivered by a benevolent victor?

Like the modern United States, the East India Company was preoccupied with prestige. Its crab-like progress across the Indian Subcontinent was marked by wars which demonstrated that its modern, well-trained armies were invincible. But the margin of technological advantage was thin, and native princes did all in their power to narrow it further. In the 1790s Tipu Sultan, the ruler of Mysore, decided on the path that would be followed by Saddam Hussein. He imported French muskets and artillery and European officers to train his men. Not quite weapons of mass destruction, but frightening enough at the time. They scared the company and the government in London, then at war with revolutionary France.

The upshot was an ultimatum: Disarm or be overrun. Mysore was invaded and Tipu killed at Seringapatam in 1799. The same formula was applied in the next 50 years against the Maratha states, Nepal and the Sikhs, who obligingly invaded the company’s territories, removing the need for an ultimatum. The principle was one that is understood in the White House: A dominant power’s authority rests on a monopoly of modern weaponry and the will to use it ruthlessly.

When the security of British India was imperilled, its rulers used force to neutralize the threat. Ironically this tactic was once applied against the United States. During the 1837 rebellion in Canada, a number of Americans collected arms for the insurgents and hired a vessel to carry them across the St Lawrence. Alerted, the British sent a small force across the river, landed at Buffalo, seized the ship, set it on fire and sent it downstream and over the Niagara Falls. Although its sovereignty had been violated, the US government conceded that this coup de main was legal on the grounds that Canada’s security was endangered.

This established a precedent in international law. More commonly, imperial powers turned to the pre-emptive strike as an instrument for enhancing prestige, maintaining a favorable balance of power, and to unnerve potential challengers. When the Zulu king Cetewayo began buying repeating rifles for his impis, a British Army invaded Zululand in 1879. The Zulu defeat at Ulundi by massive firepower was a warning to the region that Britain had the weapons to induce cooperation or submission. The same message was conveyed by the Allies in the first Gulf War.

While the redcoats trudged through Zululand, the press was demonising Cetewayo. He was a warlike tyrant, master of a formidable killing machine, who ruled through fear and witchcraft. This was comforting news for the public, for whom the empire now represented the extension of peace and civilization. Sharp, unequal tropical wars were presented as a prelude to a golden age of impartial, honest government under which Queen Victoria’s new subjects would enjoy personal security and opportunities for moral and physical betterment.

Above all — and this was a matter of passionate concern for a nation that cherished personal freedom — slavery would disappear. The will to eliminate slavery everywhere was as strong in Britain as the desire for universal democracy is in America today.

After the 1896 campaign in Nigeria, in which a mediaeval army had been routed by one armed with machine-guns and artillery, an illustrated journal showed local rulers swearing on the Qur’an to abolish slavery. A glowing electric light bulb, symbol of modernity, adorned the stamps issued by the East Africa Company, symbolizing the end of a dark past of slavery and despotism and the beginning of a bright future for the people of Uganda.

It was a theme close to the heart of the imperial bard, Kipling. When the US was setting up a colonial administration in the Philippines, he called upon its people to shoulder the “white man’s burden”. War (the Filipinos resisted) must be followed by regeneration under a kindly, paternal government dedicated to its subjects’ welfare. Otherwise, imperial wars of pacification were no more than greedy power politics that the public might find morally repugnant.

It was just as well that Britain had its “civilizing” mission to reassure voters and the rest of the world of its altruistic intentions. Public opinion was touchy about imperial campaigns. Exactly 100 years ago, there was unease about the invasion of Tibet, a pre-emptive blow struck to forestall Russian interference. There was none, and the skirmishes were massacres that sickened British officers. “I hate it,” one told his wife, “these poor Devils are brave men and they haven’t got the weapons we have. They fight to the bitter end.”

The front-line imperial soldier needed the assurance that what he was doing was morally right. Merely performing a duty prescribed by politicians was not enough: During 1919 and 1920 some British soldiers and sailors sent to northern Russia to buttress anti-Communist forces mutinied because they were not convinced that the war was justified. This was exceptional, but nonetheless a reminder that servicemen and women need to know they are risking their lives for an honorable and morally desirable cause.

This is understood by Tony Blair, hence his revival of benevolent imperialism. At heart, he is one of those thoroughly decent, clean-limbed, former prefects who once found themselves manning the outposts of empire. He sincerely wants to change things for the better. His dreams of a resuscitated Iraq under an upright and well-meaning administration would have been applauded by generations of liberal imperialists. It is not a bad vision; the old imperialism was not without flaws, but for many of its subjects it provided a welcome stability and opportunities for advancement.

Paradoxically, Blair’s prospect of a redeemed and happy Iraq was shared by one of its architects, TE Lawrence. In the 1920s he hoped that the infant state would progress onwards and upwards to become Britain’s first “brown dominion”, the Australia of the Middle East. But Lawrence also knew that for benevolent imperialism to work it needed civil peace. This was why he championed the use of bombers to chastize anyone who endangered the Pax Britannica in Iraq. Critics of aerial policing were appalled: How could you simultaneously claim to be the enlightened banner bearer of civilization and employ ferocious methods of coercion? The old dilemma of imperialism remains unresolved.

(The writer’s most recent book is ‘Warrior Race: A history of the British at war’ — Abacus)