Ngala Chome, PhD candidate at Durham University, has a great review of Al Shabaab recruitment and attacks in Kenya since 2011, and why the group has been able to stage a lot more attacks in Kenya (96.4% of recorded attacks between 2008-16) relative to other troop contributing countries engaged in Somalia (see map):
Kenya may have suffered these attacks since it is considered a key ally of the West. But why is Al-Shabaab (an Al-Qaeda affiliate) targeting Kenya more than it is other countries in the region, such as Ethiopia and Uganda, which also have close ties with the West and have fought Al-Shabaab in Somalia? To what extent does Al-Shabaab attack Kenya for the reasons it publicly gives? Will Al-Shabaab, for example, stop targeting Kenya if the Kenya Defence Forces pulled out of Somalia?
…. The Global Terrorism Database (GTD) recorded 14 more attacks before September 2011, and then 49 in 2012, 35, in 2013, 80 in 2014, 42 in 2015, and 45 in 2016. While the GTD is yet to provide figures from 2017, existing evidence shows that of the 302 trans-border attacks perpetrated by Al-Shabaab from 2008-2016, 3 occurred in Ethiopia, 5 in Uganda, 2 in Djibouti and 291 in Kenya. Brendon Cannon and Dominic Pkalya, in a recent article, have argued that beyond sharing a border with Somalia, Al-Shabaab targets Kenya more than other frontline states because of the opportunity spaces linked to Kenya’s international status and visibility, its relative free and independent media that widely publicizes terrorist attacks, a highly developed and lucrative tourism sector that provides soft targets, expanding democratic space and high levels of corruption. In sum, these variables play into Al-Shabaab’s motivations and aid planning and execution of acts that aim to fulfil the group’s quest to survive – as it losses more ground in Somalia – by maintaining its relevance on the global stage.
For a broader understanding of the dynamics driving insurgency in the Horn, check out Michael Woldemariam’s Insurgent Fragmentation in the Horn of Africa: Rebellion and its Discontents and Inside Al-Shabaab by Harun Maruf, Dan Joseph and Christopher Anzalone.