There have been times in the past 10 days when you could listen to David Cameron in the House of Commons and hear not the voice of the Coalition in 2011, but that of Tony Blair from 2002-3. The same well-spoken urgency, the same high morality, the same sincere concern for his fellow human beings, the same confidence of being on the right side of history. Only the intended beneficiary of the proposed military action is different: the besieged anti-Gaddafi forces in Libya, rather than the Kurds or the Marsh Arabs of Iraq.
And you might ask, with some incredulity, how could it be – how could it possibly be – that the next-but-one British Prime Minister has somehow managed to escape the inoculating effect of Iraq? Yesterday, David Davis – then shadow home secretary, now a back-bencher – had reinforced Mr Cameron's appeal for Libyan no-fly zone. As Mr Cameron had said "deliverable", so Mr Davis said "eminently do-able". Simple, easy. That ill-fated "cakewalk" again. Across the Atlantic the response was a good deal more circumspect.
It is a bitter irony that the anniversary of the start of the Iraq war should fall precisely this weekend. Eight years after the battles for Baghdad and Basra, the UN Security Council has given approval for an exclusion zone over another Arab land. The legacy of Iraq haunts every move.
This much Barack Obama at least has recognised. As momentous events sweep the Arab world, his administration has consistently chosen to follow rather than lead. Pressed by allies to offer early support for the protesters in Egypt, or take sides over the fighting in Libya, the White House offered nothing. The one member of his administration whom Mr Obama retained from the Bush years has been the most publicly cautious. Donald Rumsfeld's successor at the Pentagon, Robert Gates, said that enforcing even a no-fly zone would be tantamount to a declaration of war, concerned about becoming embroiled in another country's civil war.
The post-invasion anarchy in Iraq left its mark. But it is not only this memory that prescribed caution in the US and wariness on the part of Arab opposition groups that might, under other circumstances, have sought American support. At the most basic level, the Iraq war has sapped military capability and money. The US still has almost 50,000 troops deployed there. Nato forces, with the US and Britain supplying by far the largest contingents, are still fighting in Afghanistan. Arguably, Iraq is a reason they are still there a decade on – because operations in Afghanistan took second place, at a key juncture, to Iraq. Whatever the reason, the consequence is that, in combat on two fronts, even the United States cannot spare much more manpower or hardware for use beyond its own borders.
At a psychological level, Iraq undermined US national confidence, and faith everywhere in US power. What had been sold as a justified and straightforward intervention turned out to be neither. None of the pressure on the US to mount action in North Africa could in any way be described as intelligence-led; on the contrary, the revolts there took the outside world, like almost everyone in the region, by complete surprise.
But public opinion, especially in the US and Britain, now cocks a sceptical ear when a government considers armed intervention. Is the evidence there, and even if it is, is remedying the situation a job that can realistically be done? The Iraq experience has planted doubt. As widely forecast at the time, Iraq has also tarnished the case for humanitarian intervention. Mr Blair's penchant for using the military "to do good" can be seen as a response to the West's failure to prevent the genocide in Rwanda.
The ostensible success of Britain's intervention in Sierra Leone and then of international efforts to protect Bosnians and Kosovars against Serbs helped to bolster a humanitarian justification for invading Iraq. Without a demonstrated emergency, however, there was no legal cover. Nor, even in strictly humanitarian terms, did the action work. Living standards in many parts of the country are only now starting to recover.
Perhaps the most enduring consequence of Iraq, however, will prove to be the political constraints it has placed on Western action anywhere, but especially in an Arab country, even when the cause might seem unimpeachably just. President Obama was elected on a platform that included not just a pledge to withdraw from Iraq, but a renunciation of everything the Iraq debacle stood for: the rush to military force, the idea of the US as the global gendarme, the proselytising of Western-style democracy, and the demonisation of Islam.
In trying to banish that past, Mr Obama stressed that the US would not try to impose anything on anyone; that countries were responsible for their own destinies, and that any action would be decided and taken collectively, and only with the legal sanction of the UN. Such considerations led him to hold back over Egypt, despite much urging that he jump in sooner.
With Libya, the stakes are far higher, as Gaddafi appears to be in a position to erase the opposition unless it receives outside help. But this time the US has been intent on doing everything by the book. Now the no-fly zone has been authorised by the UN Security Council, after what the Foreign Secretary, William Hague, described as a tremendous amount of work. It does not bear the fingerprints of the United States, and has its roots in the region, as reflecting the wishes of the Arab League. But the price of these precautions has been delay.
Supporters of intervention will breathe a sigh of relief and hail this as the anti-Iraq model. And it is easy to conclude that eight years ago George Bush picked the wrong fight. If you want to foster democracy, why not invest in a country where opposition forces are already championing it on their own? But it is a bit late for such regrets now.
Mr Cameron may also fancy that, as one of the first to call for action on Libya, he was exorcising the ghost of Iraq from UK foreign policy. In so doing, though, he risks underestimating the suspicion that Iraq has left in its wake. Mr Obama understands the real cost of the Iraq war all too well – and whatever comes next in Libya, the latest addition to the bill may be years of civil strife in North Africa.