A year after Osama bin Laden was killed, how relevant is al-Qaida? In the decade since 9/11, Bin Laden was always a symbol rather than an operational commander. His death did not do much to disrupt the group as an organisation.
And yet his death was very important, less because of its impact on al-Qaida than because of Bin Laden's unique position in American demonology.
President Barack Obama trumpets as one of his main achievements his administration's success in tracking Bin Laden down and eliminating him.
Similarly, no US administration can afford to be seen by American voters as derelict in pursuing al-Qaida.
But, aside from killing Bin Laden, haven't the Arab Spring uprisings and protests over the last year knocked away one of al-Qaida's main ideological justifications - that dictatorships in the Muslim world could not be peacefully overthrown?
There are two main reasons why al-Qaida has survived the death of Bin Laden.
US security officials speak of it as if it was structured like the Pentagon, with ranking officers whose killing by drones, or death squads, would disrupt the organisation.
Yet it was always much more ramshackle than this. Few of the al-Qaida militants killed over the last year are irreplaceable.
A further reason is that its most powerful elements have always been franchisees not under the control of any core group.
This was true of al-Qaida in Mesopotamia, led by Abu Musab al-Zarqawi, which, starting in 2003, became a lethally effective organisation in Iraq. Al-Qaida in Mesopotamia was always distinct from the core group of leaders around Bin Laden.
Similarly in Pakistan, where the core of al-Qaida is supposedly based, there are plenty of people who have experience in guerrilla warfare - not all of them al-Qaida.
Yemen, likewise, has the advantage of being a mosaic of different power centres with a weak central state.
Unlike Iraq, al-Qaida has tried to launch attacks on the US, which might just have succeeded. It controls much of Abyan province east of Aden and made a show of strength in the last few days by arranging to release 73 government soldiers it had captured.
The problem for al-Qaida is that being associated with the organisation in any way immediately creates a host of enemies.
Weakened though it may be, al-Qaida will not fade from the headlines. This is partly because headline writers have got used to its existence as a universal bogeyman.
US counter-terrorism and intelligence officers say that al-Qaida could never again carry out an onslaught as devastating as 9/11. They may well be right.
On the other hand, the very length of time it took for the US to find Bin Laden and his family, though they had been living in the same house for years, may show that their own level of competence, in contrast to their numbers and budgets, has not improved much since the World Trade Centre was destroyed.