Yesterday’s commemorations of the September 11 attacks on America confirmed that the most devastating terrorist outrages the world has seen have not lost their power to shock and move. Three years on the reciting of the names of the 2,749 New York victims reminded us of the sheer scale of the human loss. Three thousand children lost a parent that day and many more have been lost since. Those attacks marked the start of the war on terror, a war that is likely to go on for many years. It also marked a profound shift in American foreign policy, making it willing to intervene more aggressively than at any time for a generation. The result has been the destruction of the Taliban regime in Afghanistan, which gave succour to Osama Bin Laden and Al-Qaeda, and the violent overthrow of Saddam Hussein.

The anniversary has inevitably provoked another bout of soul-searching. On one side are the critics who argue that the United States, with Britain in tow, has been dancing to Osama Bin Laden’s tune. He knew the September 11 attacks would provoke a military response and deepen divisions between the Muslim world and the West. He also calculated that Al-Qaeda was incapable of being destroyed by force. In one sense he was right. Bin Laden has evaded capture and the world seems a more dangerous place, with Beslan added to the list of post-September 11 terrorist outrages that includes Bali, Madrid, Riyadh, Casablanca and Jakarta. Nation building in the aftermath of the military operations has also been bungled.

Sir Jeremy Greenstock, the prime minister’s former envoy to Iraq, was right when he said the allies were drawn into war by Al-Qaeda. But Al-Qaeda had for a decade become bolder because it thought the West lacked the stomach for a fight. When earlier attacks met with a less than resolute response from Washington, the fanatics kept raising the stakes all the way to that attack on the World Trade Center. It is also undeniable that sooner or later Saddam’s bloodthirsty regime had to be confronted. Iraq, like Germany in the 1930s, wanted to overthrow the settlement imposed upon it after it lost a war of aggression. It represented a danger to the stability of the Middle East and, if not immediately, a threat to the West. If mistakes have been made in the aftermath of two superbly executed military campaigns, the answer is to correct them.

Skilful diplomacy might dry up some of the well-springs of hatred. More intelligent Russian leadership could separate extremists in Chechnya from those with legitimate grievances. Some settlement of the rancorous Israeli-Palestinian dispute would undoubtedly have wider repercussions beyond that small strip of territory. But there will still remain a body of fanatics whose hatred of the West cannot be satisfied by any political solution. They will seek any means to strike us, the deadlier the better. And while there are rogue states tempted to give them aid, we have no choice but to fight. The critics can carp. But think how loudly they would be wailing had Washington retreated into fortress America.