It's a victory because Bin Laden's existence was a reminder of the impotence of the US and all its allies.

It was evidence that the superpower could be struck with impunity. For all its technology and firepower, the US and its satellite states, including Australia, proved unable to strike back against the architect of the September 11 terror attacks.

While he was alive, he was a standing taunt to Western power and a source of encouragement and satisfaction to his fans and followers.

And it's Pyrrhic because Bin Laden's provocation to the US was immensely more successful than the terrorist had hoped. He said as much, and he's right.

Terrorism is a tool of the weak against the strong. Its potency is not in the harm it inflicts but in the reaction it provokes.

Terrorism is most damaging when it prods the strong into using its own strength against itself.

That is precisely what Bin Laden achieved. Not in the initial US reaction of invading Afghanistan, which was a rational and globally-supported effort to deny terrorism a safe haven and repair a failed state.

It was the US decision to invade Iraq, using September 11 and Bin Laden as pretext, and supported by the UK and Australia, that proved so destructive.

Bin Laden died knowing that he had not only killed 1,900 people in his attacks on the US. He had also successfully goaded the US into pointlessly invading Iraq, damaging US credibility, sacrificing more than 4,000 of its own troops, hundreds of allies' troops, and over 100,000 Iraqi civilians.

And the cost to the US taxpayer, at some $1 trillion, is 2,500 per cent greater than the approximately $40 billion in direct damage caused by the Septemeber 11 attacks.

Washington's unwise reaction to Bin Laden gave him his greatest achievement and his greatest source of strength.

It made him a hero to millions. In some countries of the Islamic world, he was more popular than George Bush or Barack Obama. Instead of seeing him as the vicious, unprincipled butcher he really was, they saw him as a folk hero.

And these people will now look to him as a martyr.