1. Quintan Wiktorowicz and John Kaltner, “Killing in the Name of Islam: Al-Qaeda’s Justification for September 11,” Middle East Policy Council Journal 10, no. 2 (Summer 2003), https://www.mafhoum.com/press5/147S29.htm.
2. The Arabic term emir al mu’minin, or leader of the faithful, has historically been applied to leaders with a claim to legitimacy among all Muslims, originating from the second caliph, Umar ibn al Khattab. The term has since been controversially used by leaders of various movements within Islam to gain broader support.
3. Anne Stenersen, “Al Qaeda’s Foot Soldiers: A Study of the Biographies of Foreign Fighters Killed in Afghanistan and Pakistan Between 2002 and 2006,” Studies in Conflict and Terrorism 34, no 3 (2011): 174.
4. Gall, The Wrong Enemy, 16–17.
5. Stenersen, “Al Qaeda’s Foot Soldiers.”
6. David Kilcullen, Counterinsurgency (New York: Oxford University Press, 2010), 213–14.
7. Bruce Hoffman, “World: Analyst Assess the Global War on Terror,” interview by Heather Maher, Radio Free Europe / Radio Liberty, December 22, 2006, https://www.rferl.org/a/1073632.html.
8. Pew Research Center, “Global Public Opinion in the Bush Years (2001–2008),” December 18, 2008, https://www.pewglobal.org/2008/12/18/global-public-opinion-in-the-bush-years-2001-2008/.
9. As part of Saddam Hussein’s push to co-opt religiosity in Iraq, Abu Bakr al Baghdadi, along with many other high-ranking Islamic State leaders attended the Islamic University of Baghdad, which was impossible to attend without being thoroughly vetted by the Baath party or having family members within the party. When the United States overthrew the Iraqi government, Baghdadi and his cadre of militant leaders had a preexisting network of individuals with a shared educational and religious background and mutual connections through which to form AQI/ISI and later the Islamic State. Baghdadi and others shared the Saddamists’ brutality, tradecraft, and deeply rooted hatred of the Shia. Michael Weiss and Hassan Hassan, ISIS: Inside the Army of Terror, 2nd ed. (New York: Regan Arts, 2016).
10. David Lesch, “Walking a Fine Line: Foreign Fighters and Syria,” in Foreign Fighters, Sovereignty, and Counter-Terrorism: Selected Essays, ed. Michael Noonan (Philadelphia, PA: Foreign Policy Research Institute, 2010), 68, https://www.fpri.org/wp-content/uploads/2015/08/ForeignFightersSovereigntyCounterTerrorism_Noonan.pdf; Brian Fishman, ed., Bombers, Bank Accounts and Bleedout: Al Qa’ida’s Road In and Out of Iraq (West Point, NY: Combating Terrorism Center, 2008), https://www.ctc.usma.edu/posts/bombers-bank-accounts-and-bleedout-al-qaidas-road-in-and-out-of-iraq.
11. Hegghammer, “The Rise of Muslim Foreign Fighters,” 60–61.
12. Brian Fishman and Joseph Felter, Al-Qa’ida’s Foreign Fighters in Iraq: A First Look at the Sinjar Records (West Point, NY: Combating Terrorism Center, December 2007), 7–8, https://www.ctc.usma.edu/posts/al-qaidas-foreign-fighters-in-iraq-a-first-look-at-the-sinjar-records.
14. Ibid., 20.
15. Weiss and Hassan, ISIS: Inside the Army of Terror, 25.
16. Ibid., 16–17.
17. Ibid., 17.
18. William McCants, The ISIS Apocalypse: The History, Strategy, and Doomsday Vision of the Islamic State, repr. ed. (New York: Picador, 2016), 7.
19. The last journalist to interview Osama bin Laden, Pakistan’s Rahimullah Yusufzai, noted that Abu Musab al Zarqawi responded to al Qaeda senior leadership’s warning about the pitfalls of focusing on Shia instead of Americans by declaring “killing Americans is learned behavior, but killing Shia is innate.” Personal interview with Rahimullah Yusufzai by Thomas M. Sanderson, Peshawar, Pakistan, January 17, 2013.
20. The al Askari Shrine is one of the holiest mosques in Shia Islam, exceeded in importance only by the shrines in Najaf and Karbala.
21. McCants, The ISIS Apocalypse, 7.
22. Jaysh Rijal al-Tariqah al-Naqshabandia (JRTN)—a neo-Baathist militant organization—was also involved in the antigovernment campaign and was prominent in Mosul, Kirkuk, and Salah al-Din. JRTN was the prominent antigovernment insurgency among the Tribal Military Councils (Sunni tribal fighters) and played a role in welcoming the Islamic State into Mosul without alienating the population.
23. Institute for the Study of War, “ISW Blog: Al Qaeda in Iraq’s ‘Breaking the Walls’ Campaign Achieves Its Objectives at Abu Ghraib—2013 Iraq Update #30,” ISW Blog, July 28, 2013, https://iswresearch.blogspot.com/2013/07/al-qaeda-in-iraq-walls-campaign.html.
24. Imarat Kavkaz (also known as the Caucasus Emirate) is a militant Islamist organization established in the North Caucasus in 2007 with the goal of establishing an Islamic Caliphate in Northern Caucasus. Members of the group split between support for Jabhat al Nusra and the Islamic State.
25. Imam Bukhari Jamaat (also known as Katibat Imam al Bukhari) translates as Imam Bukhari's Group and is a majority Uzbek group allied with Jabhat al Nusra. Katibat al Tawhid wal Jihad, which translates as the Battalion of Monotheism and Jihad, which is also allied with Jabhat al Nusra. Sabri’s Jamaat translated as Sabri's Group, and also known as the Aleppo Uzbeks, fought alongside the Islamic State beginning in 2014. Caleb Weiss, “Uzbek groups part of new offensive in southern Aleppo,” Threat Matrix: A Blog of the Long War Journal, June 7, 2016, https://www.longwarjournal.org/archives/2016/06/uzbek-groups-part-of-new-offensive-in-southern-aleppo.php
26. The Islamic Movement of Uzbekistan (1998) and the Islamic Jihad Union (2002) both predate the Syrian civil war and were established in Central Asia. Though both groups were traditionally allied with al Qaeda and the Taliban, the IMU broke with tradition to pledge bayat to Abu Bakr al Baghdadi. The IJU continues to support al Qaeda and its affiliates. Thomas Joscelyn and Bill Roggio, “Central Asian Groups Split Over Leadership of Global Jihad,” Long War Journal, August 24, 2015, https://www.longwarjournal.org/archives/2015/08/central-asian-groups-split-over-leadership-of-global-jihad.php.
27. Thomas Hegghammer and Aaron Y. Zelin, “How Syria’s Civil War Became a Holy Crusade,” Washington Institute, July 7, 2013, https://www.washingtoninstitute.org/policy-analysis/view/how-syrias-civil-war-became-a-holy-crusade.
28. Transnational Threats Project research interview with fundraisers in Kuwait, 2011; and Thomas Hegghammer, “Syria’s Foreign Fighters,” Foreign Policy, December 10, 2013, https://foreignpolicy.com/2013/12/09/syrias-foreign-fighters/.
29. Estimates are between 3,000–11,000, though ISCR believes the “true figure” to be above 8,500. “ICSR Insight: Up to 11,000 Foreign Fighters in Syria; Steep Rise among Western Europeans,” International Centre for the Study of Radicalisation, December 17, 2013, https://icsr.info/2013/12/icsr-insight-11000-foreign-fighters-syria-steep-rise-among-western-europeans/.
32. The first iteration of al Qaeda in Iraq (Tanzim Qaidat al Jihad fi Bilad al Rafidayn) rebranded itself as the Islamic State of Iraq in October 2006. However, the group continued to be commonly referred to as al Qaeda in Iraq, and the two names were used interchangeably until AQI/ISI transformed into the Islamic State of Iraq and al Sham in April 2013. For the sake of clarity, this report uses AQI until 2013, and Islamic State thereafter.
33. The Arabic word muhajir translates as immigrant, and is used to refer to fighters who have traveled to fight in a location other than their home country.
34. McCants, The ISIS Apocalypse, 93.
35. Liz Sly, “Al-Qaeda Disavows Any Ties with Radical Islamist ISIS Group in Syria, Iraq,” Washington Post, February 3, 2014, https://www.washingtonpost.com/world/middle_east/al-qaeda-disavows-any-ties-with-radical-islamist-isis-group-in-syria-iraq/2014/02/03/2c9afc3a-8cef-11e3-98ab-fe5228217bd1_story.html.
36. In a war of movement, “the goal of the insurgency . . . is to bring about the collapse of the established government or the withdrawal of the occupying power. . . . As the insurgency gains control over the country, the insurgent leadership becomes responsible for the population, resources, and territory under its control. . . . Based on the conditions set earlier, an effective resistance or insurgency establishes an effective civil administration, establishes an effective military organization, provides balanced social and economic development, mobilizes the population to support the resistance organization, and protects the population from hostile actions.” U.S. Army, “FM 3-24.2 (FM 90-8, 7-98) Tactics in Counterinsurgency” (Department of the Army, March 2009), https://fas.org/irp/doddir/army/fmi3-24-2.pdf; U.S. Army, “TC 18-01 Special Forces Unconventional Warfare” (Department of the Army, November 30, 2010), 18-01, https://www.apd.army.mil/epubs/DR_pubs/DR_c/pdf/web/tc18_01.pdf.
37. Baghdadi’s proclamation of himself as emir al mu’minin was controversial within the Muslim world, as it has historically applied to leaders with a claim to legitimacy within Islam. Baghdadi’s use of the title was his attempt to legitimize the Islamic State and its apocalyptic worldview within Islamic theology.
38. Dan Roberts and Spencer Ackerman, “US Begins Air Strikes against Isis Targets in Iraq, Pentagon Says,” The Guardian, August 8, 2014, https://www.theguardian.com/world/2014/aug/08/us-begins-air-strikes-iraq-isis.
39. Gold Coast Bulletin, “Fight against the Islamic State working, says bishop, as foreign fighter numbers drop,” February 1, 2016, https://search.proquest.com.proxy.library.georgetown.edu/docview/1761352758?pq-origsite=summon.
40. “U.S. Envoy Says Number of Islamic State Foreign Fighters Dropping,” Radio Free Europe / Radio Liberty, February 23, 2016, https://www.rferl.org/a/islamic-state-foreign-fighters-dropping/27569890.html.
41. Griff Witte, Sudarsan Raghavan, and James McAuley, “Flow of Foreign Fighters Plummets as Islamic State Loses Its Edge,” Washington Post, September 9, 2016, https://www.washingtonpost.com/world/europe/flow-of-foreign-fighters-plummets-as-isis-loses-its-edge/2016/09/09/ed3e0dda-751b-11e6-9781-49e591781754_story.html.
42. “Islamic State Calls for Attacks on the West during Ramadan in Audio Message,” Reuters, May 22, 2016, https://www.reuters.com/article/us-mideast-crisis-islamicstate-idUSKCN0YC0OG .