Why the US needs to blame anyone but locals for its latest catastrophe

It was always the same story. If it wasn't the enemy you were fighting, it was the enemy you knew you'd have to fight in the future.

So when the killers of Baghdad on Tuesday slaughtered 20 UN staff, with the UN's local proconsul, Sergio Vieira de Mello, the Americans embarked on one of their familiar flights into fancy. If it wasn't Saddam's "diehard remnants" who were tormenting them, it must be al-Qa'ida's "remnants" who are destroying America's best efforts to produce democracy in Iraq (though not Afghanistan); "foreign Arab" fighters were creeping over the border from Iran or Syria.

This was the line from the "Coalition Provisional Authority" yesterday: don't, for God's sake, produce proof of home-grown opposition, or the whole "liberation" of Iraq might look rather dodgy. Blame it on al-Qa'ida, on "Ansar al-Islam", on "terrorists" coming from Saudi Arabia or Syria or Afghanistan. But, during the war against the American invasion of Iraq, weren't there two suicide bombings in Nasariyah, one by a man, the second by two women? Weren't they Iraqis? And isn't it possible an Iraqi Sunni resistance movement - for let us be frank and accept that the Shia have not yet joined the resistance war, though they will - destroyed the UN headquarters on Tuesday? Only yesterday did it emerge that the bomber was probably a suicider.

Months ago, when Donald Rumsfeld, the US Defence Secretary who in a previous incarnation pleaded with Saddam (circa 1983) to reopen the US embassy in Baghdad, arrived in the Iraqi capital to address his troops, he warned of "terrorist" organisations at large in Iraq. Some of us wondered what he was talking about. Hadn't the US just defeated Iraq?

But then we realised he was spinning a narrative for journalists to grasp if the "Saddam remnants" line wore out. There would be other evildoers to blame, other antagonists in the "war on terror" to single out.

Sure enough, the "outside" guerrillas have now been brought centre-stage, whether or not they exist, to explain why US rule in Iraq is coming undone. The US can crush Saddam. It can kill his sons. But still it cannot control Iraq.

This, in a sense, is the last heirloom that Saddam has handed to President George Bush: you can occupy this country, he is saying, but you can't rule it. Saddam created enough pseudo-Wahabist groups to let off steam during his reign. Talk about Islam, they were told, but not about politics. But the moment the regime collapsed, these organisations, which had always been hostile to Saddam, were left to their own devices, and immediately opposed US rule in Iraq. They, not al-Qa'ida, or anyone else, are running this butchery of a war against America and its friends in Iraq.

When the resistance to the Americans began in Lebanon in 1982-83, it started with stone-throwing after six months. Yet the assaults on the Americans in Baghdad are coming at a speed six times as fast. Six months ago, it would have been impossible to imagine such a scenario. Certainly, al-Qa'ida could not have organised its legions so quickly. So even Osama bin Laden may have something to learn from this debacle.