What now for al-Qaeda?

First break down the network into its constituent elements: the hardcore leadership, the various affiliated groups that have some kind of organisational link to al-Qaeda and the ideology, al-Qaeda-ism.

The hardcore leadership has always been defined as Osama and his Egyptian associate, Ayman al-Zawahiri, and a few score associates in Pakistan. Zawahiri is apparently still alive. However, the ageing former paediatrician has none of the charisma of Osama. He is good on ideology, strong on strategy and even organisation but can never be the focal point for active followers, whether aspirant jihadis or veteran militants, that Osama was.

There are younger leadership figures, some who have been promoted as al-Qaeda has tried to fight its creeping marginalisation in recent years. But people such as Abu Yayha al-Libi, who is in his mid-40s, can never replace “the sheikh”. The central leadership of al-Qaeda has been splintered in recent years, often pitting Saudi Arabian, Egyptian and Libyan militants against each other. It is now likely to definitively fracture.

What of the affiliate groups or the “network of networks”? Decentralising was always an integral part of the strategy of Osama. Al-Qaeda was conceived as an umbrella group, channelling and focusing the diverse energies of the various groups active across the Islamic world in the 1990s. This worked for a while but the main regional groups now — Al-Qaeda in the Arabian Peninsula (largely the Yemen), Al-Qaeda in the Maghreb (largely Algeria) and Al-Qaeda in Iraq are largely independent of the main leadership. Each is rooted in specific local factors and history. Their alliance with al-Qaeda was usually nominal in any case.

This reminds us how al-Qaeda was always only one of scores of radical groups that together constituted the dynamic, varied and evolving phenomenon of Sunni Muslim violent extremism. Though the death of Osama will fundamentally change the landscape of contemporary militancy it will thus not necessarily have a big immediate effect on affiliate groups beyond discouraging their leadership by showing how, even if it takes 10 years, fugitives do eventually get caught and killed.

The final question is perhaps the most important. What will the effects be on the ideology? Here the situation is less clear. Osama's greatest success was to make his particular interpretation of radical Islamism globally known. There were other strands of militant thinking and strategy around in the late 1990s but 20 years of “propaganda by deed” made Osama's the dominant one. A thriving jihadi subculture has emerged. Al-Qaeda has become, in many ways, a social movement. Osama's death means the removal of the figure at the centre of this construct. This is undoubtedly important.

Also, many of the myriad factors that have fed radical militancy in recent decades — some of which stretch back decades or even centuries in the Islamic world or in the Islamic world's relationship with the West — are still as potent as ever. We are living in a new era of polarisation, conspiracy theory and religious identity. The strategic impact of Osama's actions depended in part on the reaction of his enemies, particularly the United States. The consequences of his death do so too.

That said, in recent years the increasing marginalisation of al-Qaeda — culturally, socially and geographically — has been very clear. The Arab Spring demonstrated how Osama's message had been rejected by those hundreds of millions he once sought to radicalise and mobilise. Al-Qaeda had orchestrated no major successful attack for more than five years. The recruits were coming to the makeshift Pakistani camps but only in enough numbers to assure the core group's survival not its success, at least not in the short term.

The most likely scenario in the future is continuing low-level violence and threat shifting around the periphery of the Islamic world depending on local circumstances and the emergence of new leaders. “My life or death does not matter. The awakening has started,” Osama boasted in late 2001. It will be at least another decade before we know if he was right. — © Guardian Newspapers Limited, 2011