Through their suffering, naked Iraqi prisoners have inflicted far greater collateral damage on their enemies than the Republican Guards ever did in their full battle regalia.

The fallout from the infamous Abu Ghraib prison continues to shake the foundations of the seemingly impregnable Bush and Blair administrations, and threatens the careers of several senior politicians and generals.

Whoever coined that old cliche "A picture is worth a thousand words" had not figured on the power of the image of a young American woman soldier gleefully pointing at a naked prisoner and making the thumbs-up sign with her other hand.

The same soldier is also seen in other photos, including a particularly revolting one of her holding a leash with another naked prisoner at the other end with a dog collar around his neck.

Most Muslim countries, especially in the Middle East, are no strangers to torture and physical abuse. Most rulers in the region are kept in power by these methods, and their citizens have endured literally centuries of coercion. But what is genuinely shocking and abhorrent in the images from Abu Ghraib is the sexual degradation the victims have been subjected to, particularly by female soldiers.

Clearly, the intention was to humiliate prisoners and photograph them undergoing this ordeal so that they could be reminded at a later date if they stepped out of line.

The American government has pretended shock and horror (as opposed to "shock and awe") over the actions of their soldiers at Saddam's old house of horrors. But the reality is that there were complaints from released victims as well as organizations like Amnesty International and the Red Cross right from the early days of the occupation just over a year ago.

It is clear that the soldiers were carrying out instructions from intelligence agencies like the CIA, and the Pentagon can hardly claim ignorance of the inhuman methods being used to soften up prisoners.

While the American and British public have no problems about images of bombs and missiles pounding residential areas and killing thousands of non-combatants in the heat of battle, they are revolted by the pictures of helpless prisoners being cold-bloodedly degraded and tortured.

Here in Britain, there is much talk of dumping Blair in the aftermath of this scandal. Even those who supported the war are appalled by what is being done in their name. Bush's popularity ratings have plummeted and for the first time, it seems that he may lose the November elections.

Two separate lessons emerge from the horrors of Abu Ghraib. Firstly, leaders cannot take support for foreign adventures for granted: after the first flush of patriotic fervour, the conduct of war and its aftermath are crucial for continuing support.

In Vietnam, the American military machine was defeated not in the jungles of Indochina but in the living rooms of Middle America where day in and day out, televised images of the war invaded the consciousness of the average citizen.

Gradually, political support for the war ebbed away as the number of body bags kept mounting, while the suffering of the Vietnamese people became a major political issue.

The last nail in the American determination to seek a military victory was the searing image of a naked young girl fleeing her burning village, her mouth open in a harrowing scream of terror.

This single photo did more to force the Americans to leave than any military strategy adopted by the Vietcong. The first lesson then is that in democracies, public opinion can force a change in policy, and wars are won and lost in the media as much as on the battlefield.

The second lesson is that in wars, terrible things invariably happen. When you put soldiers trained to kill and follow orders blindly in charge of their enemies, you are inevitably going to get the horror story that has emerged from Abu Ghraib.

The young men and women responsible for the bestial acts we have been witnessing were raised on a steady diet of movies depicting Arabs as a subhuman species.

'Rag-heads' and 'dope-heads' are some of the milder epithets used by American troops to describe Iraqis. This demonization of the foe is standard procedure. But in the case of the Arabs, their image in America has been deliberately distorted over decades to the point where the average young American sees him as an inferior being incapable of the same feelings the rest of us have. Once brainwashing has achieved this level of contempt for somebody, the conditions for brutalizing him have been created.

In authoritarian states, both the decision to go to war and when to pull out are taken by the ruling oligarchy without any reference to public opinion. Thus when Yahya Khan waged war on the Bengalis of East Pakistan, or the Soviet Union invaded Afghanistan, they fought on until they were defeated on the battlefield.

Along the way, the armies of both dictatorships committed countless crimes against humanity, but their people were largely uninformed and powerless to influence events.

Since time immemorial, we have maintained what are in reality mercenary armies to do our killing for us. Especially in these days of hi-tech weapons, the days of volunteer armies are long past.

When a soldier makes the military a career and the source of his livelihood, he is unlikely to refuse to follow an illegal order, thereby jeopardizing the chances of a promotion.

Also, the first thing soldiers learn is to obey an order from a superior officer without question. Loyalty to his regiment and his national flag are drummed into him from the day he joins the military.

Unsurprisingly, this conditioning produces a trained killing machine for whom the concept of human rights is alien. Put this soldier in charge of enemy prisoners and tell him to soften them up for questioning, and you are guaranteed to get Abu Ghraib, no matter which army is involved.

So when we send soldiers out to do our killing for us, it is hypocritical to expect them to fight and treat prisoners under the Geneva Convention. This document, like any constitution or body of laws, is only as good as the intention of the people responsible for implementing them.

When soldiers are told they have to succeed at any cost, the dignity of their captives is the last thing they will be concerned with. It has long been held that truth is the first casualty in war. Humanity is probably the second.