Francis Fukuyama's Iraq recantation has received keen attention on both sides of the Atlantic. Like many US conservatives, he now distances himself from what has been done in the neocons' name by the Bush administration. Of course, we welcome every sinner that repenteth, but the people who seem most deserving of respect are those clever Americans who got it right in the first place. Most of my US military acquaintances opposed the invasion. They did not doubt the coalition's ability to defeat Saddam's army swiftly and topple his regime. It was uncertainty about what would follow that rang warning bells. They identified from the outset precisely the difficulties that Messrs Cheney, Rumsfeld and Wolfowitz contemptuously dismissed.
In October 2002, when it became evident that Bush was determined to invade Iraq, the US Army War College's strategic studies institute undertook a study of a prospective occupation. Some bright soldiers and diplomats got together with two military academics, Dr Conrad Crane and Dr Andrew Terrill. The fruits of their labours were published in February 2003, before the first shot was fired.
Re-reading the study today, it seems stunningly prescient. First, it highlighted previous failures to address the problems of occupation, notably after the 1991 Gulf war. A senior commander on the ground, it said, "could get no useful staff support to assess and plan for post-conflict issues like hospital beds, prisoners and refugees, complaining later that he was handed 'a dripping bag of manure' that no one else wanted".
In 2003, the study predicted, after a brief initial honeymoon "suspicion of US motives will increase ... A force initially viewed as liberators can rapidly be relegated to the status of invaders ... Regionally, the occupation will be viewed with great scepticism, which may only be overcome by the population's rapid progress towards a secure and prosperous way of life ... The establishment of democracy or even some sort of rough pluralism in Iraq ... will be a staggering challenge". It warned that exile groups, the focus of Pentagon hopes, did not possess the domestic support to form a credible Iraqi interim administration.
Crane and Terrill forecast the alienation of Sunnis dispossessed of power, and the difficulties of reconciling a society riven by religious and tribal divides. They anticipated an insurgency, and highlighted the importance of training US soldiers in the specialised skills of low-intensity combat against guerrillas in the midst of a civilian population.
They identified suicide-bombing as the insurgents' likely tactic of choice, noting that Israel had been able to stem this threat only by building its security wall, not an option in Iraq: "All Arabs ... are now learning stunning lessons about the effectiveness of suicide bombers."
They cautioned against disbanding the Iraqi army after winning the war: "To tear apart the army ... could lead to the destruction of one of the only forces for unity within the society ... [It] also raises the possibility that demobilised soldiers could affiliate with ethnic or tribal militias."
Crane and Terrill summarised their conclusions thus: "To be successful, an occupation ... requires much detailed inter-agency planning, many forces, multi-year military commitment, and a national commitment to nation-building. Recent American experiences with post-conflict operations have generally featured poor planning, problems with relevant military-force structure, and difficulties with a handover from military to civilian responsibility."
They forecast the need for strong engineer and civil affairs back-up for combat units, and suggested that US forces would face "possible severe security difficulties ... The administration of an Iraqi occupation will be complicated by deep religious, ethnic and tribal differences, which dominate Iraqi society. US forces may have to manage and adjudicate conflicts among Iraqis that they can barely comprehend".
"An exit strategy will require the establishment of political stability, which will be difficult to achieve given Iraq's fragmented population, weak political institutions and propensity for rule by violence."
There is today much criticism of American and British intelligence about Iraq before the invasion. We know that both the CIA and the Secret Intelligence Service got it wrong about weapons of mass destruction. Yet allied commanders had access to a mass of shrewd analysis, of which the Crane-Terrill study, from a respected US army institution, is only the most striking example. All such material was tossed aside, of course, because it did not fit the administration's agenda.
Intelligence and predictive analysis can never be more useful than the political and service chiefs to whom they are submitted. In Afghanistan today, almost all the smart diplomats, soldiers, journalists and intelligence-gatherers agree that Nato plans to deploy a few thousand troops to support reconstruction amount to gesture strategy of the worst sort. The policy survives only because it represents the highest common factor of Nato nations' willingness to act, a pitiful political figleaf rather than a coherent military operation.
Perhaps the most important lesson of Iraq and Afghanistan is that senior soldiers on both sides of the Atlantic should be braver about saying no. Armed forces are the servants of democratic governments. But their commanders should recognise a constitutional duty to dig in their heels when invited by politicians to undertake operations they perceive as militarily unsound. This the 2003 Iraq invasion emphatically was, because of the US government's refusal meaningfully to address "phase IV" occupation planning.
Cobra II, the new book by Michael Gordon and General Bernard Trainor, which was serialised in this newspaper, makes plain that much of America's military leadership was uncomfortable with the operation, and thought the terms set by defence secretary Rumsfeld quite unrealistic. Yet the doubters stifled their feelings, and the dissenters were sidelined. There was enough ambitious, heedless top brass in the mould of General Tommy Franks to do the business.
Britain's service chiefs would have endorsed every word of the Crane-Terrill pamphlet about the requirements for occupation strategy, and were in no doubt that their American partners had done little or nothing towards fulfilling them. British commanders went ahead with doing their part anyway. They perceived this as their duty, just as they are now presiding over the token British deployment in Afghanistan, though almost no one in uniform thinks its objectives attainable with the forces available.
The Blair government ruthlessly stifles expressions of dissent within the Ministry of Defence. Yet the only way to avoid more foreign fiascos is to have an informed, ongoing public debate about what our armed forces are or are not doing. We have learned the painful consequence of dependence for enlightenment on Alastair Campbell and his "mate" John Scarlett.
Iraq has demonstrated what happens when governments are allowed to defy informed opinion and pursue ideologically driven adventures. There will come a time when the west has vital reasons to stage another armed intervention somewhere in the world. When it does, we need to feel confident that the chiefs of staff on both sides of the Atlantic will speak their minds if they are invited by government to execute a policy that they judge ill-conceived.
We ourselves, as citizens, must know enough to exploit our democratic institutions to prevent another such fiasco as Iraq. Any US soldier or civilian who read the Crane-Terrill report back in 2003 should have recognised that refusal to heed its wise strictures promised disaster, and indeed delivered it.
Max Hastings is the author of Armageddon: the Battle for Germany 1944-1945.
Guardian Newspapers Limited 2006