The five years since the Iraq invasion have changed the United States’ view of itself — and changed the Middle East. Iraq is still in a fragile state, only half a step away from civil war and soaring violence, but it is possible to set down some of the lessons learnt.

The 2008 presidential campaign in the US has begun to do that, in the cacophonous way that campaigns do, spinning out policies that would be disastrous were they to become real. But the congressional committees have been admirably tenacious in probing the mistakes of intelligence and uncontrolled spending; so has the US Army.

Britain has been less impressive in acknowledging that there may be something to be learnt, although Gordon Brown has now hinted that he may, at some point, hold an inquiry. It would be valuable to hear the Government’s formal account.

But there is no need to wait for that reckoning (which may never arrive). The past five years have produced an outpouring of personal tales and naked score-settling by the protagonists. They contradict each other, they blame each other, but they paint a full picture of what went wrong.

Intelligence

The single greatest mistake was the US reliance on Ahmad Chalabi, an Iraqi exile, who sketched for them a portrait of his country that suited his own ambitions and happened to be what they wanted to hear. He told them that the Sunni elite that had run the country under Saddam Hussein could be deposed and that the US could install leaders of its own choice (such as Chalabi, a Shia), without turmoil. More generally, Iraq has been a blunt reminder that intelligence is, in that old phrase, scraps off a rich man’s table. It was always patchy and when United Nations weapons inspectors were thrown out of Iraq in 1998 the quality plummeted.

Sanctions work

Iraq offers support for the case that sanctions sometimes work well. From what we know now about Iraq’s weapons, it is clear that Saddam was severely impeded in his quest for nuclear arms, and in rebuilding stocks of chemical weapons after the 1991 war.

Justification for war

Neither the US nor Britain can afford to go to war again with as shaky a justification, and of such contestible legality, as they did in Iraq.

True, there are problems with resting authorisation in the UN Security Council. The ability of any of the five permanent members (the US, Britain, France, Russia and China) to veto a resolution means that some proposals regarded widely as legitimate will never get backing. That was the US’s justification for not seeking the Council’s backing in the 1999 Kosovo war.

But that was less controversial because of the widespread feeling that the Serbian persecution of the province’s ethnic Albanians had to be stopped. In Iraq’s case, the US and Britain failed to get such support.

They were thrown back on a medley of reasons, none sufficient. The argument that Saddam’s breach of old UN resolutions to stop him reinvading Kuwait was weak. The claims that Iraq might attack soon collapsed with the failure to find weapons of mass destruction and the revelation about how much the US and Britain had exaggerated the strength of intelligence. Tony Blair tried to argue that humanitarian reasons were good cause, but the force of that pitch was a decade earlier, when Saddam was attacking dissidents within Iraq, or in the aftermath of the 1991 war.

The failure to get wide support undermined the invasion and peace-building, and also the US claim to be upholding international law and institutions, a charge it now has to counter.

Invasion-lite

Donald Rumsfeld’s most significant contributions as Secretary of Defence are the phrase “unknown unknowns” and the decision to invade Iraq with a force of only 100,000. The first — a description of the threats you cannot pre-empt because you don’t know they are there — has entered the language of diplomacy; the second deserves to do so only as a lesson in mistakes.

The force was great enough to take Baghdad but nothing like enough to secure the peace as the insurgency grew. In the US Army’s new operations manual, the first since 2001, it elevates peacekeeping to the same status as battlefied victory. But the implications (more troops, for longer) may undermine public support for action.

Big early mistakes

The most heated rows are over the early decisions. They are: the disdain for stopping looting; the disbanding of the Iraqi Army; “de-Baathification” to force members of Saddam’s party out of office; and, perhaps, not handing over sovereignty immediately.

All of these added fuel to the insurgency. It is now commonplace to say that disbanding the army and de-Baathification, two of the first decisions taken by Paul Bremer, the US administrator, ignited opposition. But new accounts make a case that, although the purge went too far, many US officials agreed that the top layers had to be removed.

The common impulse behind these mistakes, and behind the too-light invasion force, is the US belief that it would be welcomed as a liberator, as it was in France and Germany after the Second World War. The lesson is that this heady memory has had its day.

Torture, Guantanamo, Abu Ghraib

The US claims that the abuse of prisoners at Abu Ghraib prison, which did huge damage to its image in the Arab world, was the misjudgment of a few junior soldiers. But its defence of the systematic use of harsh interrogation techniques has not helped it to repair that, and nor has its defence of holding captives without trial at Guantanamo Bay. It is facing a sceptical Congress, legal challenge and hostile opinion abroad.

It would be hard to call this a “lesson learnt”, because the US has given barely an inch in its adherence to these techniques. This month Bush vetoed a Bill that would have outlawed the interrogation technique of “water-boarding”, among others, on the ground that it would hamper the CIA. But it would be hard to say that the US has proved that their usefulness in the War on Terror outweighs the damage to its reputation.

Britain and the south

Britain accepted too many compliments for the quiet of the south in the early years, and for the “sensitive approach” of its forces, when the wish of southern clerics for the region to stay quiet was far more important. That handicapped Britain in arguing for more money for the south and left it unprepared when violence began to rise. It should have made Britain more cautious about deepening its commitment to Afghanistan so quickly.

Afghanistan

The lesson Britain and the US should have taken from Iraq was the sheer difficulty and expense of peace-building. They appear to be appreciating that only now, in Afghanistan. Given that country’s poverty, lack of resources and neighbours with an interest in backing militants, it could be trickier for Britain than Iraq. As David Satterfield, the US co-ordinator for Iraq, told The Times (report, January 5), Iraq may turn out to be the “good war” while Afghanistan goes “bad”.

Iran

The effect of Iraq that appears to have taken the US and Britain most by surprise was the boost to Iran, a Shia country delighted to have a Shia-led Government next door. This has made it harder to constrain Iran’s nuclear ambitions. One of the lessons is the need to consider the role of the neighbours when planning military action — a lesson that Afghanistan is also driving home.

Promotion of democracy

The Iraq experience has taken the fire out of America’s self-declared mission to promote democracy. It can see — as it did in Lebanon and the Palestinian territories — that this may not put in power pro-Western leaders. Its officials have gone quiet in this goal in Central Asia and even now find it hard to end support for the undemocratic President Musharraf of Pakistan.

But it would be an unfortunate consequence if the US and Britain dropped the advocation of their own system of government and values, even if that is tempered with recognition of how messy the results can be.

Neglect of problems

The Iraq war caused the US and Britain to neglect other problems. Afghanistan tops that list, but it also includes courtship of Turkey and of Central and Eastern European countries, annoyed at their pro-US stance being taken for granted. Perhaps the only problem that has been helped by the intense focus elsewhere is the Pakistan-India feud over Kashmir, which was drained of heat once both realised that they had to combat terrorism.

Never again?

There is little mood for new military action in the US or Britain (although the US has been careful not to rule out the possibility over Iran’s nuclear ambitions). But there will be incidents requiring intervention — with better justification than Iraq. No one would play down the turmoil and grief for Iraqis of the past five years, but it would be regrettable if the misjudgments of that war had undermined the ability of the West to intevene in a just cause.

Where are they now?

Private Jessica Lynch

Three days into the war a US army convoy took a wrong turn and was attacked in Nasiriyah. Eleven US soldiers were killed and six captured, among them Private First Class Jessica Lynch, 19. When the Pentagon released dramatic footage of her rescue she became a celebrity. She denounced a version of the attack in which she fought back bravely, accusing the US military of fabricating feel-good stories. A book deal and a TV film, Saving Jessica Lynch, followed. After an honourable discharge, Private Lynch began studies at West Virginia University but took a break in January last year to give birth to a daughter. Last April she testified before a House committee investigation into whether the Pentagon misrepresented the experiences of US soldiers in Iraq and Afghanistan, sticking to her story.

Hattie Garlick

Samia Nakhoul

On April 8, 2003, in one of the most controversial incidents of the war, journalists in the Palestine Hotel were watching US tanks enter Baghdad. Samia Nakhoul, a Reuters correspondent, was on her balcony when, almost a mile away, an M1A1 Abrams angled its gun towards the hotel and fired a single shell. Ms Nakhoul suffered severe head injuries. Two cameramen died, early victims in a conflict that has taken the lives of 150 journalists. “To this day I don’t know why they fired,” Ms Nakhoul told The Times. The US claimed that its soldiers believed there was a sniper, but they had been briefed on the position of journalists.

Safety fears would scare off much of the world’s press. Reuters and The Times remained. Ms Nakhoul took 18 months to recover and is still with Reuters but not in Baghdad.

Tom Whipple

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