The global terrorist threat continued to evolve rapidly in 2015, becoming increasingly decentralized and diffuse. Terrorist groups continued to exploit an absence of credible and effective state institutions, where avenues for free and peaceful expression of opinion were blocked, justice systems lacked credibility, and where security force abuses and government corruption went unchecked. The Islamic State of Iraq and the Levant (ISIL) remained the greatest threat globally, maintaining a formidable force in Iraq and Syria, including a large number of foreign terrorist fighters. ISIL's capacity...