It was formed in 2006 by young men and until recently controlled most of southern Somalia but now its control of home territory has shrunk and it is a different group
Spectacular and deadly attacks hit football fans watching the 2010 World Cup final in a pub in Kampala, Uganda, when 74 died, and shoppers on a sunny 2013 Saturday morning in Nairobi, where 72 died at the Westgate Centre.
Inside Somalia, the country’s citizens lived under the repressive rule of an organisation that banned smoking cigarettes, watching televised sport, listening to music or even wearing a bra, all deemed un-Islamic.
Today, al-Shabaab is a very different group, and that fact holds the key to understanding its latest strike on Kenya’s Garissa University College.
Formed in 2006 by young men – al-Shabaab means ‘the youth’ in Arabic – who were the armed militia for the Islamic Courts Union, Somalia’s one-time rulers, it has been fighting the country’s Western-backed government and its allies in a war to impose a strict interpretation of Islamic law.
But its control over its home territory has shrunk considerably, as a coalition of African Union armed forces, mostly Ugandan, Burundian and Kenyan, has won back large areas of land.
The Islamists lost key sea ports at Barawe and Kismayo, through which they earned more than £1.5 million a month to buy weapons and pay fighters by controlling the export of charcoal to the Gulf and the import of untaxed sugar to smuggle to east Africa.
Most importantly, its flood of recruits has dried up. Many came from Kenyan communities culturally similar to those in Somalia, whose youth felt disenfranchised and ignored by politicians in Nairobi, Kenya’s capital.
Many others came from farther afield. Al-Shabaab’s recruitment drive reached Queen’s Park in west London, where Mohammed Emwazi, later better known as Jihadi John, travelled to Tanzania allegedly en route to join al-Shabaab.
It reached Michael Adebolajo in Lambeth, who was later arrested allegedly trying to cross from Kenya into Somalia. He went on to murder Fusilier Lee Rigby on a Woolwich pavement.
Estimates of how many foreign fighters Shabaab could field ran into hundreds, with up to 50 believed to be British passport holders. But with the rise of the Islamic State of Iraq and the Levant, wannabe jihadists now file towards the border between Turkey and Iraq, rather than that between Kenya and Somalia.
Meanwhile, President Barack Obama authorised an unprecedented number of drone strikes in Somalia. Many of al-Shabaab’s top commanders from the group’s more internationalist, hardline faction have been killed.
They include Ahmed Godane, its leader, killed in September 2014, and Abdi Nur Mahdi, its external intelligence chief, killed in February this year. A month later, Adnan Garar, suspected of masterminding the Westgate attack, died in a rain of Hellfire missiles.
Their new leader, the little-known Ahmad Umar, is understood to represent al-Shabaab’s more nationalist branch, which aims only to rule Somalia. Its appetite for global attacks is limited.
But the internationalist faction is still there, and still powerful. Keen to show Islamic State that it is still to be included in global jihad, this hardline rump of al-Shabaab needed a spectacular new strike. The 147 mostly Christian students of Garissa University College were the victims of that need to remain relevant.
Al-Shabaab’s plans, whatever they may be, are likely what prompted worried Western embassies to extend their warnings about potential new terror attacks in Kenya over Easter and beyond. Kenya’s overstretched and corruptible security agents struggle to keep a step ahead of the group’s cells.
Security analysts suggest al-Shabaab is coming towards the end of a transition from a unified Somali Islamist army, to one split between a nationalist militia with domestic ambitions, and the internationalist hardliners.
As Garissa showed, that latter faction is still deeply to be feared, especially if you are a Christian living in Muslim lands in east Africa.