The considerable variation in the way national security agencies are structured is a function of two basic factors: the state’s political and social heterogeneity and the possibility of allying with a strong external state, usually the United States. The problem, however, with fragmenting the military and security forces to achieve “coup-proofing” is that a tradeoff exists between fragmentation and assuring internal security on the one hand, and ensuring offensive capabilities to ward off external enemies, on the other. According to this model, centralized homogenous entities enjoying U.S. protection will tend to fragment their security systems most. States that duplicate their security forces least are plural societies that cannot command U.S. interest and commitment to meet their external security threats. The Palestinian Authority (PA) under Yasser Arafat was emblematic of political entities that were homogenous and enjoyed the protection of the United States and Israel, and it could therefore fragment its security forces into 12 or more security agencies compared to Eritrea, which achieved independence a year before the establishment of the PA, and maintained a very unified security apparatus to meet the threat of a vastly larger enemy—Ethiopia.
As long as Israel (and the United States and its allies) supported the PA, Arafat made do with a fragmented inefficient security structure that was nevertheless efficient enough, with Israeli security backing, to meet the major external threat—Hamas and the Jihad al-Islami in both the West Bank/Judea and Samaria and Gaza. Israel’s decision to withdraw from Gaza in December 2003 and to complete its withdrawal from Gaza by September 2005 forced the fragmented PA to face these enemies alone, leading to the loss of Gaza to Hamas. By contrast, in the West Bank/Judea and Samaria, the more fragmented PA security structure prevailed as a result of considerable security cooperation with Israel. Hamas, bereft of a close external ally, challenges a superior Israeli military and therefore has a unified security structure much like Eritrea in the 1990s.