If there is a day that a "war on terror" can end, it might have been yesterday.
The killing of Osama bin Laden is unlikely to end the threat of the terrorism he inspired, it may even raise an immediate risk of reprisals somewhere, but symbolically it is a victory.
The United States' previous president would have relished announcing the news President Barack Obama delivered yesterday, particularly if an election was approaching.
Mr Obama probably would have relished announcing it seven or eight months ago, before the mid-term congressional elections recorded disappointment with him.
Since US intelligence had located bin Laden as long ago as August, the President must have been tempted to order an attack before November. It is to his credit that he waited as long as was needed to be certain of the target and carry out the mission with success.
Bin Laden has been wanted "dead or alive" since September 11, 2001, but it is likely he was only wanted dead. Alive he would have posed as big a problem for justice as most of the terrorism suspects that Mr Obama has continued to hold at Guantanamo Base, Cuba, beyond the reach of United States laws of habeas corpus.
Mr Obama calls bin Laden's death in an attack which cost no American lives a victory for justice, but it is the justice of war.
Bin Laden was the founder of al-Qaeda, probably gave the order for the attacks on Manhattan and Washington and has been the symbol and inspiration of murder and mayhem carried out in the name of Islam ever since.
Now he will have martyr status in the twisted logic of his following but the symbolic value of his death is just as important for confidence in Western security.
Bin Laden's ability to elude US intelligence and military forces for nearly 10 years was remarkable, particularly as he was always reckoned to be in Pakistan, where he was at last found, and not in a cave in the mountains but in a city. It is a reminder that bin Laden's image has always been at odds with his true origins.
He was an urban-dwelling, Western-educated scion of a respected Saudi Arabian family. He and similarly Western-educated friends went to Afghanistan to help US-backed mujahideen defeat the Soviet occupation.
By the time the Russians withdrew, his band was looking for a new cause and called themselves al Qaeda (the base) for some sort of Islamic fundamentalist revival that they believed might be inspired by random provocative strikes against Western populations.
Al Qaeda came to the attention of Western counter-terrorism efforts years before September 11, 2001, through its attacks on US embassies in East Africa and against the USS Cole in Yemen. Its location in Pakistan was also known as were its training camps across the border in Afghanistan.
But agencies such as the CIA had few Arabic-speaking spies in the vicinity and none of this attracted much interest outside security seminars until hijacked airliners flew into the World Trade Centre and the Pentagon on that sunny morning at the dawn of the 21st century.
Bin Laden's suicide pilots literally changed the world. Air travel became subject to intensive security precautions. Hotels became targets, anywhere Western tourists congregated was considered a danger.
Dare we use the past tense now that bin Laden is dead? His legacy will cause the world to take precautions for a long time yet, but nothing on the scale of 9/11 has been allowed to happen again. Now Egypt is giving hope of better leadership in the Islamic world.
If bin Laden's life symbolised a threat his death is a symbol too. It demonstrates that vigilance is winning the war.