Despite similarities between the two nations, the situation on the ground is very different this time.
Failures in Iraq don't provide an excuse for inaction in Syria
Like early-morning fog, Iraq hangs heavy over every discussion of military intervention in Syria. It hovers in the background, the ready counter-example, the implied warning.
And, truthfully, the two do look similar. Here, again, a mere decade on, is talk of weapons of mass destruction and the thundering pronouncements from western capitals that something must be done. Here again is the blind moral certainty that the muscular militaries of the West will not "allow" the use of chemical weapons; here again the spectre of the only country to use nuclear weapons fulminating at the use of chemical warfare. Here again the sudden interest in a brutal dictatorship that western countries previously ignored or even feted. Here, again, is the divide among politicians and commentators between timid uncertainty and bellicose bellowing. And here again is the lack of a United Nations mandate and the willingness on the part of America to ignore legal niceties in favour of shattering a city and maybe a whole country.
So there are similarities and it would be foolish to deny them. Iraq and Syria, after all, share a long border and much history. But the idea that military intervention in Syria today is equivalent to the 2003 invasion of Iraq is fanciful. Indeed, it is dangerous. We are rehashing the arguments of the last decade, while Syria burns.
I was against the invasion of Iraq. Not because I liked Saddam Hussein or was in any doubt about the brutality of his regime. Not because I wanted to condemn Iraqis to living under his regime nor because I was against the idea of foreign intervention in general. But it seemed to me in the run-up to the sudden interest in Iraq after the September 11 attacks that two vital questions were not answered, often not even asked: Why Iraq? And why now?
The regime of Saddam Hussein in Iraq in 2003 posed no greater threat to the outside world or to Iraqis than it had the year previously or even the decade previously. It was a brutal dictatorship, no doubt, but it wasn't clear why it was especially dangerous all of a sudden. If Britain and America were so keen on intervention to "save" the population from a brutal regime, well, there were plenty of other candidates.
The idea that the calculus of risk had changed after September 11 was spurious. Despite Condoleezza Rice's quip that "we don't want the smoking gun to be a mushroom cloud", there was no evidence that Saddam had nuclear weapons or was on his way to acquiring them. There was no casus belli. Indeed, Tony Blair, in a curiously unguarded moment, admitted that the Iraq invasion had happened only because it could have happened at that point. Meaning that Saddam Hussein had been in America's crosshairs for years, a bitter foe in the strategically vital Middle East, and now there was an opportunity to remove him. Everything - the weapons of mass destruction, saving Iraqis, women's rights - all of that was just icing on the cake. The substance was elsewhere.
But Syria today is not Iraq 10 years ago. Most vitally, it is a nation in the midst of a revolution. Ordinary Syrians did not ask for this war, but the Assad regime launched it anyway. For two and a half years, Syrians have been fighting to overthrow him. For two and a half years, they have staved off one of the region's toughest militaries. Syrians are not asking anyone else to fight this war, they are merely asking for some help. Syria is a burning building and its people are calling for help.
Moreover, there is no ambiguity over Bashar Al Assad's actions, as there was with Saddam. The only ambiguity is why he unambiguously used chemical weapons. But on everything else, there is no mystery: Mr Al Assad has thrown everything he has at his people, torturing, raping, murdering, and destroying his way through Syria. What ambiguity is there? In Iraq, we didn't know what Saddam might do. Here we know exactly what Mr Al Assad is doing and we are leaving him to finish the job.
And that's why the hand-wringing over Syria is so astonishing. Because, while Iraq was bubbling under the surface, Syria is openly in flames. This is not the case of fighting a war of choice for undefined ends. This is a humanitarian intervention to end the massacre of civilians.
In the years after the massacre of Hama in 1982, people asked whether the world should have acted sooner. In Hama, then, perhaps 20,000 people lost their lives in a single, bloody month. In Syria today, five or six times that number, at least, have been killed, in a bloody war that has shattered almost every single major city in the country.
There must come a point where the international community says no more, when the number of civilians killed is so large that it provokes a response. Those who believed that number would have four or five digits have been proved cruelly wrong. The number of dead is well into six figures and keeps rising.
Haunted by its failures in Iraq, the international community sees everything washed in the light of Mesopotamia. The fear of failure has become fatalism.
Unable to see past Iraq, the international community is paralysed by the fog of a past war, even as a cloud of gas descends on Syrian civilians.
On Twitter: @FaisalAlYafai