Eradicating Terrorism in Asymmetric Conflict: The Role and Essence of Military Deterrence

ABSTRACT

This study quantitatively and qualitatively analyzes the impact and effectiveness of Turkey’s deterrence-oriented incapacitation effort throughout Turkey’s PKK conflict (1984–2018). By employing vector autoregressive (VAR) analysis, this study quantitatively finds that incapacitation did not reduce PKK violence over the long term and yielded a short-term counterproductive effect. Descriptive analysis asserts that while incapacitation had important mid-term deterring effects, it did not have any sustainable mitigation on the PKK insurrection. This is because, as this study argues, these deterrent impacts were not strategically converted into political gains/results. Considering the latest phase of the conflict, in which Turkey’s intra-state strife has become increasingly regionalized and lately internationalized in military and political terms with the emergence of the Syrian civil war, particularly the rise of the People’s Protection Units (YPG), this study claims that the sole application of an incapacitation-oriented eliminationist approach has become less relevant and less effective. The study suggests that deterrence should be considered within the strategic tit-for-tat game to force/compel the non-state actor to make the conflict more manageable by transforming it in a strategic way, in which strategy of deterrence is to be attached to visionary, long-term, and viable grand strategic political end-states and to be considered within the grand bargaining game.

KEYWORDS:

• Deterrence
• terrorism
• counterterrorism (CT)
• incapacitation
• Turkey
• PKK
• counterinsurgency (COIN)
• insurgency
• military operations

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Notes

1. See for instance, Richard K. Betts, “The Soft Underbelly of American Primacy: Tactical Advantages of Terror,” Political Science Quarterly 117, no. 1 (2002): 19–37; Paul K. Davis and Brian Michael Jenkins, Deterrence and Influence in Counterterrorism: A Component in the War on al Qaeda. (Santa Monica, CA: Rand Corporation, 2002); Bruno S. Frey, Dealing with Terrorism – Stick or Carrot? (Cheltenham, UK: Edward Elgar Publishing, 2004); Bruno S. Frey and Simon Luechinger, “How to Fight Terrorism: Alternatives to Deterrence,” Defense and Peace Economics 14, no. 4 (2003): 237–49; Walter Enders and Todd Sandler, “The Effectiveness of Antiterrorism Policies: A Vector-Autoregression-Intervention Analysis,” American Political Science Review 87, no. 4 (1993): 829–44.

2. See for instance, William M. Landes, “An Economic Study of U.S. Aircraft Hijacking 1961–76,” Journal of Law and Economics 21 (1978): 1–32.; Henry W. Punckun Jr. and Philip B. Mohr, “Military Deterrence of International Terrorism: An Evaluation of Operation El Dorado Canyon,” Studies in Conflict & Terrorism 20, no. 3 (1997): 267–280; Laura Dugan Gary LaFree, and Alex R. Piquero, “Testing a Rational Choice Model of Airline Hijackings,” Criminology 43, no. 4 (2005): 1031–1065; Walter Enders and Todd Sandler, “Transnational Terrorism in the Post–Cold War Era,” International Studies Quarterly 43, no. 1 (1999): 145–67.

3. See for instance, Deterring Terrorism: A Model for Strategic Deterrence, edited by Elli Lieberman, (New York, NY: Routledge, 2018); Robert F. Trager and Dessislava P. Zagorcheva, “Deterring Terrorism: It Can Be Done,” International Security 30, no. 3 (2006): 87–123.

4. Richard Shultz, “Coercive Force and Military Strategy: Deterrence Logic and the Cost-Benefit Model of Counterinsurgency Warfare,” Western Political Quarterly 32, no. 4 (1979): 444–66; Austin T. Turk, “Confronting Enemies Foreign and Domestic: An American Dilemma?” Criminology & Public Policy 1, no. 3 (2002): 345–50; Mustafa Cosar Ünal, “The Dichotomy in the Perception, Conception and the Response to Terrorism: The Case of the PKK,” Counter Terrorism in Diverse Communities 90, no. 2011 (2011): 268; John Bradford Braithwaite, “Thinking Critically About the War Model and the Criminal Justice Model for Combating Terrorism,” SSRN Electronic Journal, 2002; Mustafa Cosar Ünal, Counterterrorism in Turkey: Policy Choices and Policy Effects Toward the Kurdistan Workers’ Party (PKK) (New York, NY: Routledge, 2012).

5. Kemal Kirisci and Gareth M. Winrow, The Kurdish Question and Turkey: An Example of a Trans-State Ethnic Conflict (Oxon, UK: Routledge, 2013), 7–8; Counterterrorism in Turkey.

6. Detailed casualty figures are provided in Appendix-A (Table A-1).

7. Andrew H. Kydd and Barbara F. Walter, “The Strategies of Terrorism,” International security 31, no. 1 (2006): 49–80.

8. Mustafa Cosar Ünal, “Strategist or Pragmatist: A Challenging Look at Ocalan’s Retrospective Classification and Definition of PKK’s Strategic Periods Between 1973 and 2012,” Terrorism and Political Violence 26, no. 3 (2014): 420–22.

9. Ünal, “Is It Ripe Yet? Resolving Turkey’s 30 Years of Conflict With the PKK,” Turkish Studies 17, no. 1 (2016): 91–125.

10. Metin Gürcan and Mustafa Coşar Ünal, “Reaching a Balance of Resolve: the Enduring Conflict Between Turkey and the PKK,” In Deterring Terrorism (New York, NY: Routledge, 2018), edited by Elli Lieberman 193–230.

11. Ersel Aydinli, “Between Security and Liberalization: Decoding Turkey’s Struggle With the PKK,” Security Dialogue 33, no. 2 (2002): 220–22; Ünal, Counterterrorism in Turkey, 3.

12. The PKK declared a number of unilateral ceasefires for various reasons, but Turkey did not respond to them in order not to legitimize the PKK, except for a de facto situational armistice for certain periods during the resolution process. For more details see Mustafa Cosar Ünal, “Counterinsurgency and Military Strategy: An Analysis of the Turkish Army’s COIN Strategies/Doctrines,” Military Operations Research 21, no. 1 (2016): 55–88.

13. E.g., Hurriyet News “Until No terrorist remains” accessed on 15 December 2018, available at http://www.hurriyet.com.tr/tumgeneral-tarakci-son-terorist-kalana-kadar-m-40576932.

14. Güneş Murat Tezcür. “When Democratization Radicalizes: The Kurdish Nationalist Movement in Turkey,” Journal of Peace Research 47, no. 6 (2010): 775–89.

15. See for instance, Tarik Eser, “The Impact of the Turkish Policies and Actions Toward the PKK Terrorist Organization: A Time Series Analysis” (Ph.D. Dissertation, Sam Houston State University, 2007).

16. See Enders and Sandler, “The Effectiveness of Antiterrorism Policies”; Patrick T. Brandt and Todd Sandler, “A Bayesian Poisson Vector Autoregression Model,” Political Analysis 20, no. 3 (2012): 292–315; Carlos Pestana Barros, José Passos, and Luis A. Gil-Alana. “The Timing of ETA Terrorist Attacks,” Journal of Policy Modeling 28, no. 3 (2006): 335–346; Carlos Pestana Barros, “An Intervention Analysis of Terrorism: The Spanish ETA case,” Defence and Peace Economics 14, no. 6 (2003): 401–412; Syed Ali Raza and Syed Tehseen Jawaid, “Terrorism and Tourism: A Conjunction and Ramification in Pakistan,” Economic Modelling 33 (2013): 65–70.

17. See for instance, Bahar Araz-Takay, K. Peren Arin, and Tolga Omay, “The Endogenous and Non-Linear Relationship Between Terrorism and Economic Performance: Turkish Evidence,” Defence and Peace Economics 20, no. 1 (2009): 1–10; Mete Feridun and Muhammad Shahbaz, “Fighting Terrorism: Are Military Measures Effective? Empirical Evidence From Turkey,” Defence and Peace Economics 21, no. 2 (2010): 193–205; Pinar Derin-Güre, “Separatist Terrorism and the Economic Conditions in South‐Eastern Turkey,” Defence and Peace Economics 22, no. 4 (2011): 393–407.

18. Ünal, The Dichotomy in the Perception.

19. Ünal, Counterterrorism in Turkey.

20. Arie W. Kruglanski, Martha Crenshaw, Jerrold M. Post, and Jeff Victoroff, “What Should This Fight be Called? Metaphors of Counterterrorism and Their Implications,” Psychological Science in the Public Interest 8, no. 3 (2007): 97–133.

21. Ünal, “Counterinsurgency and Military Strategy.”

22. Marina Miron, “First-Party COIN: Approaches of Choice in Peru, Turkey and Sri Lanka in Strategic Perspective” (Ph.D. Dissertation, University of New South Wales, 2018).

23. Doron Almog, “Cumulative Deterrence and the War on Terrorism,” Parameters 34, no. 4 (2004): 4–19.

24. Classical deterrence theory that had emerged in the Cold War era is not applicable in the contemporary COIN campaigns.

25. Almog, “Cumulative deterrence,” 9.

26. Ibid.

27. Marina Miron, “On Irregular Wars, Insurgencies and How to Counter Them: Enemy and Population-centric Approaches in Comparative Perspective,” Revista Científica General José María Córdova 17, no. 27 (2019): 457–480.

28. Ibid.

29. LaFree, Dugan, and Piquero, “Testing a Rational Choice Model”; Frey, Dealing with Terrorism; Frey and Luechinger, “How to Fight Terrorism”; Landes, “An Economic Study of US Aircraft Hijacking 1961–76”; Enders and Sandler, “The Effectiveness of Antiterrorism Policies”; Ünal, The Dichotomy in the Perception.

30. Enders and Sandler, “The Effectiveness of Antiterrorism Policies”; Michael Kenney, From Pablo to Osama (University Park, PA: Pennsylvania State University Press, 2007), 56; Jeffrey Ian Ross, “Structural causes of oppositional political terrorism: Towards a causal model,” Journal of Peace Research 30, no. 3 (1993): 317–329; Lafree Dugan, and Piquero, “Testing a Rational Choice Model”; Frey and Luechinger, “How to Fight Terrorism.”

31. Lafree Dugan, and Piquero, “Testing a Rational Choice Model”; Enders and Sandler, “The Effectiveness of Antiterrorism Policies.”

32. Frey and Luechinger, “How to Fight Terrorism.”

33. Mendes, “Certainty, Severity”; Kenney, “From Pablo to Osama.”

34. Frey, Dealing with Terrorism.

35. Braithwaite, “Thinking Critically”; Lawrence W. Sherman, “Defiance, Deterrence, and Irrelevance: A Theory of the Criminal Sanction,” Journal of Research in Crime and Delinquency 30, no. 4 (1993): 445–473.

36. Tom R. Tyler, “Multiculturalism and the Willingness of Citizens to Defer to Law and to Legal Authorities,” Law & Social Inquiry 25, no. 4 (2000): 983–1019; Sherman, “Defiance, Deterrence, and Irrelevance.”

37. Martha Crenshaw, “How Terrorism Ends” (US Institute of Peace, Washington, DC, 1999): 9.

38. Braithwaite, “Thinking Critically.”

39. Martha Crenshaw, ed., Terrorism in Context (University Park, PA: Pennsylvania State University Press, 2010); Paul Wilkinson, Terrorism Versus Democracy: The Liberal State Response (Oxon, UK: Routledge, 2006).

40. Shultz, “Coercive Force and Military Strategy”; Turk, “Confronting Enemies Foreign and Domestic”; Crenshaw, “How Terrorism Ends”; Frey and Luechinger, “How to Fight Terrorism”; Mark Irving Lichbach, “Deterrence or Escalation? The Puzzle of Aggregate Studies of Repression and Dissent,” Journal of Conflict Resolution 31, no. 2 (1987): 266–97; John A. Nevin, “Retaliating Against Terrorists,” Behavior and Social Issues 12, no. 2 (2003): 109–28.

41. Daniel Byman, “The logic of Ethnic Terrorism,” Studies in Conflict & Terrorism 21, no. 2 (1998): 149–69.

42. Landes, “An Economic Study of US Aircraft Hijacking 1961–76”; Prunckun Jr. and Mohr, “Military Deterrence of International Terrorism”; Dugan, Lafree, and Piquero, “Testing a Rational Choice Model”; Enders and Sandler, “Transnational Terrorism in the Post-Cold War Era.”

43. Lee E. Dutter and Ofira Seliktar, “To Martyr or Not to Martyr: Jihad is the Question, What Policy is the Answer?” Studies in Conflict & Terrorism 30, no. 5 (2007): 429–43.; 2: Michele L. Malvesti, “Bombing bin Laden: Assessing the Effectiveness of Air Strikes as a Counter-Terrorism Strategy,” Fletcher Forum of World Affairs 26, no. 1 (2002): 17.

44. Frey and Luechinger, “How to Fight Terrorism”; Lichbach, “Deterrence or Escalation?”; Nevin, “Retaliating.”

45. Trager and Zagorcheva, “Deterring Terrorism” 89.

46. Richard K. Betts, “The Soft Underbelly of American Primacy.”

47. Gregory D. Miller, “Terrorist Decision Making and the Deterrence Problem,” Studies in Conflict & Terrorism 36, no. 2 (2013): 132.

48. Ibid., 135.

49. Ibid., 145.

50. Laura Dugan and Erica Chenoweth, “Moving Beyond Deterrence: The Effectiveness of Raising the Expected Utility of Abstaining from Terrorism in Israel,” American Sociological Review 77, no. 4 (2012): 597–624.

51. Almog, “Cumulative Deterrence and the War on Terrorism,” 15.

52. Paul K. Davis and Brian Michael Jenkins, “A System Approach to Deterring and Influencing Terrorists,” Conflict Management and Peace Science 21, no. 1 (2004): 3–15.

53. Boaz Ganor, “Terrorist Organization Typologies and the Probability of a Boomerang Effect,” Studies in Conflict & Terrorism 31, no. 4 (2008): 56.

54. Michael C. Horowitz, Evan Perkoski, and Philip BK Potter, “Tactical Diversity in Militant Violence,” International Organization 72, no. 1 (2018): 140.

55. Laure Paquette, Terrorist-Insurgent Thinking and Joint Special Operational Planning Doctrine and Procedures (Macdill, FL: JSOU, 2010).

56. Perkoski and Potter, “Tactical Diversity in Militant Violence,” 143–4.

57. Paul J. DiMaggio and Walter W. Powell, “The Iron Cage Revisited: Institutional Isomorphism and Collective Rationality in Organizational Fields,” American Sociological Review, 48/2 (1983): 147–60; Daniel A. Levinthal, “Organizational Adaptation and Environmental Selection-Interrelated Processes of Change,” Organization Science 2, no. 1 (1991): 140–45; Barry R. Posen, “Nationalism, the Mass Army, and Military Power,” International Security 18, no. 2 (1993): 80–124.

58. Emanuel Adler, “Complex Deterrence in the Asymmetric-Warfare Era,” in Complex Deterrence: Strategy in the Global Age, edited by T.V. Paul, Patrick M. Morgan, and James J. Wirtz (Chicago: University of Chicago Press, 2009) 85–108; Ivan Arreguín-Toft, “Unconventional deterrence: How the Weak Deter the Strong,”; Paul, Morgan, and Wirtz, eds., Complex Deterrence 204; Amos Malka, “Israel and Asymmetrical Deterrence Paul, Morgan, and Wirtz, Complex Deterrence.” Comparative Strategy 27, no. 1 (2008): 15.

59. Frey, Dealing with Terrorism; Frey and Luechinger, “How to Fight Terrorism.”

60. Turk, “Confronting Enemies Foreign and Domestic”; Braithwaite, “Thinking Critically”; Frey, Dealing with Terrorism; Nevin, “Retaliating.”

61. Wilkinson, Terrorism Versus Democracy.

62. Gary L. Geipel, “Urban Terrorists in Continental Europe after 1970: Implications for Deterrence and Defeat of Violent Nonstate Actors,” Comparative Strategy 26, no. 5 (December 13, 2007): 439–67.

63. Brian M. Jenkins, “Should Our Arsenal Against Terrorism Include Assassination” (No. P-7303, Rand Corp., Santa Monica CA, 1987); Seth G. Jones “Fighting Networked Terrorist Groups: Lessons from Israel,” Studies in Conflict & Terrorism 30, no. 4 (2007): 281–302.

64. Matt Frankel, “The ABCs of HVT: Key Lessons From High Value Targeting Campaigns Against Insurgents and Terrorists,” Studies in Conflict & Terrorism 34, no. 1 (2010): 17–30.

65. Audrey Kurth Cronin, “How al-Qaida ends: The Decline and Demise of Terrorist Groups,” International Security 31, no. 1 (2006): 7–48.

66. Jenkins, “Should Our Arsenal Against Terrorism Include Assassination.”

67. Jenna Jordan, “When Heads Roll: Assessing the Effectiveness of Leadership Decapitation,” Security Studies 18, no. 4 (2009): 719–55.

68. Jenna Jordan, “Attacking the Leader, Missing the Mark: Why Terrorist Groups Survive Decapitation Strikes,” International Security 38, no. 4 (April 2014): 20.

69. Aaron Mannes, “Testing the Snake Head Strategy: Does Killing or Capturing its Leaders Reduce a Terrorist Group’s Activity?” The Journal of International Policy Solutions 9 (2008).

70. Patrick B. Johnston, “Does Decapitation Work? Assessing the Effectiveness of Leadership Targeting in Counterinsurgency Campaigns,” International Security 36, no. 4 (April 2012): 47–79.

71. Bryan C. Price, “Targeting Top Terrorists: How Leadership Decapitation Contributes to Counterterrorism,” International Security 36, no. 4 (April 2012): 9–46.

72. Ibid., 43–4.

73. Jon Cauley and Eric Iksoon Im, “Intervention Policy Analysis of Skyjackings and Other Terrorist Incidents,” The American Economic Review 78, no. 2 (1988): 27–31; Enders and Sandler, “The Effectiveness of Antiterrorism Policies.”

74. Wenger and Wilner, Deterring Terrorism, 302.

75. Thomas C. Schelling, “Arms and influence” in Strategic Studies, 2nd ed., edited by Thomas G. Mahnken and Joseph A. Maiolo, (Oxon, UK: Routledge, 2008), 96–114.

76. Crenshaw, Terrorism in Context; Turk, “Confronting Enemies Foreign and Domestic”; Braithwaite, “Thinking Critically”; Lichbach, “Deterrence or Escalation?”; Nevin, “Retaliating.”

77. Frey, Dealing with Terrorism; Turk, “Confronting Enemies Foreign and Domestic.”

78. Shultz, “Coercive Force and Military Strategy”; Frey, Dealing with Terrorism; Crenshaw, “How Terrorism Ends”; Frey and Luechinger, “How to Fight Terrorism”; Nevin, “Retaliating.”

79. Wenger and Wilner, Deterring Terrorism.

80. Frey, Dealing with Terrorism.

81. Ünal, Counterterrorism in Turkey, 163–67.

82. Uprooting these people from their original habitat is a fragile policy choice with many complications and ramifications and only its relation to the logic of deterrence is discussed here. Yet, moral rectitude of such policy is beyond this study’s scope.

83. Mustafa Coşar Ünal, “Terrorism Versus Insurgency: a Conceptual Analysis,” Crime, Law and Social Change 66, no. 1 (2016): 21–57.

84. Kilcullen describes this approach as “enemy-centric counterinsurgency” in Turkey’s official discourses; however, it is more generally referred to as “counterterrorism.” See Kilcullen, “Two Schools.”

85. Nevruz (newroz in original) is a traditional holiday for Kurds and certain other populations denoting arrival of spring.

86. Kemal Kirişçi, “The Kurdish Issue in Turkey: Limits of European Union Reform,” South European Society and Politics 16, no. 2 (2011): 335–349.

87. Mary Lou O’Neil, “Linguistic Human Rights and the Rights of Kurds” in Human Rights in Turkey, edited by Zehra F. Kabasakal Arat, (Philadelphia, PA: University of Pennsylvania Press, 2007): 72–86.

88. Mustafa Cosar Ünal, “Opening a Door for Return to Home: Impact and Effectiveness of Turkish Repentance Laws,” Studies in Conflict & Terrorism 39, no. 2 (2016): 128–164.

89. Aydınlı, “Between Security and Liberalization,” 210–22; Ünal, “Terrorism Versus Insurgency.”

90. Özlem Kayhan Pusane, “Turkey’s Kurdish Opening: Long Awaited Achievements and Failed Expectations,” Turkish Studies 15, no. 1 (2014): 81.

91. Turkish official discourse toward the PKK has always been in the frame of counterterrorism. Please see Ünal, “Terrorism Versus Insurgency” for a more detailed and technical discussion on this account. Both terms, insurgency and terrorism, are used in this study according to the original study’s approach when defining the PKK.

92. Ersel Aydinli and Nihat Ali Ozcan. “The Conflict Resolution and Counterterrorism Dilemma: Turkey Faces its Kurdish Question,” Terrorism and Political Violence 23, no. 3 (2011): 438–57; Michael M. Gunter, “The Kurdish Question in Perspective,” World Affairs 166, no. 4 (2004): 197–205; Kirişci and Winrow, The Kurdish Question and Turkey; Matthew Kocher, “The Decline of PKK and the Viability of a One-State Solution in Turkey,” Democracy and Human Rights in Multicultural Societies 93 (2007); Ünal, Counterterrorism in Turkey.

93. Güneş Murat Tezcür, “Ordinary people, extraordinary risks: Participation in an ethnic rebellion,” American Political Science Review 110, no. 2 (2016): 247–264.

94. Ünal, “Is It Ripe Yet?”; Ünal, Counterterrorism in Turkey.

95. Kim and Yun, “What Works?”

96. Kocher, “The Decline of the PKK and the Viability of a One-State Solution in Turkey.”

97. Ünal, Counterterrorism in Turkey; Ünal, “Counterinsurgency.”

98. Aydınlı, “Between Security and Liberalization.”

99. Kayhan-Pusane, “Turkey’s Kurdish Opening,” 728.

100. Ünal, “Is It Ripe Yet?”

101. The PKK employed unilateral ceasefires for various strategic and pragmatic reasons, some of which include recouping, attempted resolution initiatives, pre-election periods, and so forth (beyond the scope and focus of this study). Except for one ceasefire during the resolution process Turkey did not acknowledge them and continued with military operations. And there existed violent incidents even in this period.

102. Casualties include Turkey’s CT operations in N. Iraq that serves as the PKK’s safe haven.

103. Personal Communication with Erin Miller in 2007, a senior consultant for the GTD program based in University of Maryland.

104. Irfan Ciftci and Sedat Kula, “The Evaluation of the Effectiveness of Counterterrorism Policies on the PKK-Inflicted Violence During the Democratization Process of Turkey,” Journal of Terrorism Research 6 no. 1 (January 2015): 27–42.

105. Patrick T. Brandt and John T. Williams, Multiple Time Series Models: Series: Quantitative Applications in the Social Sciences (Thousand Oaks, CA: Sage Publications, 2007).

106. Walter Enders, Applied Econometric Time Series: Fourth Edition (Hoboken, NJ: John Wiley & Sons, 2015).

107. Frey, Dealing with Terrorism; Turk, “Confronting Enemies Foreign and Domestic”; Nevin, “Retaliating.”

108. A reduced form of the VAR model takes each variable as a linear function of its own past values and the past values of all other endogenous variables and serially uncorrelated error terms. See Stock and Watson, “Vector autoregressions.”

109. The lag length for the standard VAR model is determined based on the Lag Order Selection Results, see Appendix-B.

110. This VAR model is built from a parsimony standpoint, reflecting a match with the available data, and they are also naive for the sake of brevity and simplicity in the interpretation of the results.

111. Enders and Sandler, “The Effectiveness of Antiterrorism Policies.”

112. Impulse responses trace out the response of current and future values of each of the variables in the system to a one-unit increase in the current value of one of the VAR errors. So, in this study, the impulse response function shows the response of PKK-induced violence to a one standard deviation increase/shock (over the error term) in the incapacitated PKK members.

113. Brandt and Williams, Multiple Time Series Models.

114. Brandt and Williams, Multiple Time Series Models; James H. Stock and Mark W. Watson, “Vector Autoregressions,” Journal of Economic Perspectives 15, no 4 (Fall 2001): 101–115.

115. Appendix-B includes all of the preliminary steps/procedures of VAR estimates with specific test results. These include basic themes of the VAR, Block Exogeneity Test, Augmented Dickey-Fuller Test, Akaike information criterion (AIC) and the Final prediction error (FPE), Serial Correlation LM, and Stability test.

116. Results are statistically significant where both error lines (dashed lines) are away (either above or below) from the zero-line indicating 0.95 confidence level.

117. To plot the results for all the analyses, the author used E-views 11, a multiple time series analysis software package.

118. Mathew Kocher, “The Decline of the PKK and the Viability of a One-State Solution in Turkey” (see note 3 above).

119. Abdullah Öcalan, Kürdistan Devriminin Yolu (Manifesto) (Köln, Germany: Weşanên Serxwebûn, 1978).

120. Ünal, “Counterterrorism in Turkey.”

121. Region and emergency rule are, throughout the paper, refer to Turkey’s southeast and east region that is populated with Kurds and where the PKK claimed independence. Most of this region was under emergency rule between 1987 and 2002.

122. Ünal, “Strategist or Pragmatist.”

123. Ünal, “Counterinsurgency.”

124. Kayhan-Pusane, “Turkey’s Kurdish Opening,” 81; Aydınlı, “Between Security and Liberalization.”

125. “Historical documentary on the PKK’s withdrawal in 1999,” accessed in May 10, 2018, https://www.youtube.com/watch?v=Eezt7TaFDLY.

126. Abdullah Öcalan, “There could be either Military or Political Solution in 1994,” Serxwebun 148, no. 4 (April 1994), available at http://www.serxwebun.org/arsiv/148/.

127. There was not a collective state approach and a consensus on resolving the conflict with a conciliatory approach or with a viable exit strategy.

128. Ünal, “Is It Ripe Yet?”

129. DiMaggio and Powell, “The Iron Cage Revisited”; Levinthal, “Organizational adaptation and environmental selection”; Posen, “Nationalism.”

130. Adler, “Complex Deterrence in the Asymmetric-Warfare Era”; Arreguin-Toft, “Unconventional Deterrence,” 204; Malka, “Asymemetrical Deterrence,” 15.

131. Turk, “Confronting Enemies Foreign and Domestic”; Braithwaite, “Thinking Critically”; Frey, Dealing with Terrorism; Nevin, “Retaliating.”

132. Frey, Dealing with Terrorism; Frey and Luechinger, “How to Fight Terrorism.”

133. Ünal, “Is It Ripe Yet?” 11.

134. Ünal, Counterterrorism in Turkey.

135. KCK is the successor of Koma Komalen Kurdistan (KKK) created in 2005 by ÖÖcalan as part of his Democratic Confederalism concept and vision for pro-PKK Kurds inhabiting Turkey, Syria, Iraq, and Iran.

136. Ünal, “Is It Ripe Yet?”

137. William Zartman, “Negotiating İnternal, Ethnic and İdentity Conflicts in a Globalized World,” International Negotiation 11, no. 2 (2006): 261.

138. Ibid.

139. Ibid.

140. Ünal, “Counterinsurgency.”

141. Casualty figures for security forces and civilians are reliable as they are part of a related judicial process.

142. “Terror Results for 265 days,” Milliyet, March, 28 2016, accessed on June 17, 2016, http://www.milliyet.com.tr/tsk-bilancoyu-acikladi-4-bin-432-gundem-2217174/.

143. Berkay Mandıracı, “International Crisis Group: Turkey’s PKK Conflict: The Death Toll,” https://www.crisisgroup.org/europe-central-asia/western-europemediterranean/turkey/turkey-s-pkk-conflict-death-toll (accessed July 30, 2016).

144. See Appendix-A (Table A-2) for detailed incapacitation figures.

145. “Turkish Army, so far, finished the PKK 5 times,” Milliyet, July 6, 2010, accessed October 17, 2015, http://www.milliyet.com.tr/sozun-bittigi-yerdeyiz-/siyaset/haberdetay/06.07.2010/1259717/default.htm.

146. Schelling, Arms and Influence, 34.

147. Frey, Dealing with Terrorism.

148. Michael Howard, “When are Wars Decisive?” Survival 41, no. 1 (1999): 126–135.

^1. Patrick T. Brandt and John T. Williams, Multiple Time Series Models: Series: Quantitative Applications in the Social Sciences (Thousand Oaks, CA: Sage Publications, 2007); James H. Stock and Mark W. Watson, “Vector Autoregressions,” Journal of Economic Perspectives 15, no 4 (Fall 2001): 101–115.

^2. Brandt and Williams, Multiple Time Series Models p. 9.

^3. Ibid.

^4. Walter Enders, Applied Econometric Time Series (Hoboken, NJ: John Wiley & Sons, 2003).

^5. Stock and Watson, “Vector Autoregressions.”

^6. Walter Enders and Todd Sandler, “The Effectiveness of Antiterrorism Policies: A Vector-Autoregression-Intervention Analysis,” American Political Science Review 87, no. 04 (1993): 829-844.

^7. James T. McClave and Frank H. Dietrich II, Statistics For Business and Economics: Fourth Edition (San Francisco, CA: Dellen Publishing Company, 1988).

^8. Brandt and Williams, Multiple Time Series Models.

^9. Specification of lag length for all preliminary tests is based on default selection by the system itself. For the actual VAR analysis, specific test is run to determine the lag length for the entire VAR systems.

¹⁰ If a series is not stationary, it does not converge normal distribution at the convergence rate of$\frac{\mathrm{\partial }}{\mathrm{\partial }t}({\alpha }_i{\rho }_i)+\mathrm{\nabla }.({\alpha }_i{\rho }_i\overline{U_i})=0$. So, we cannot use the critical T-statistics produced for normal distribution. Therefore, unit root test produced individual T-statistics for each variable tested against stationarity and specific T-statistics at 1% and 5% confidence level are indicated in the related Table.

^11. James Douglas Hamilton, Time Series Analysis, vol. 2 (Princeton, NJ: Princeton University Press, 1994); Brandt and Williams, Multiple Time Series Models; Stock and Watson, “Vector Autoregressions.”

^12. Ibid.

^13. Causality requires three criteria in the most generic definition: existence of a temporally consistent relationship; a statistically significant correlation; and a non-spurious relationship. While the first two criteria can be tested, the relationship being non-spurious and the direction of the relationship cannot be determined other than with related theories that explain the relationship between the variables. Yet, a result of non-causality from the Granger Causality Test does not mean that there is no contemporaneous correlation between the variables, it only means that the past values of variables are not predictive for the current values of other variable.

^14. Hamilton, Time Series Analysis p.307

^15. Ibid.

^16. If any of the serial correlation tests show evidence of serial correlation in residuals, the solution is to add additional lags into each equation in the VAR analysis.

^17. Brandt and Williams, Multiple Time Series Models; Enders, Applied Econometric Time Series.

^18. Brandt and Williams, Multiple Time Series Models p.65; Hamilton, Time Series Analysis; Stock and Watson, “Vector Autoregressions.”

^19. Ibid.; Enders, Applied Econometric Time Series.

^20. Impulse response function assumes that the error (that belongs to one of the variables in the system and increased at one unit to get the response function) returns to zero in subsequent periods (decays/fades out) and all other errors are equal to zero.

^21. Brandt and Williams, Multiple Time Series Models; Stock and Watson, “Vector Autoregressions.”

1. According to the most generic definition, impulse responses trace out the response of current and future values of each of the variables in the system to a one-unit increase in the current value of one of the VAR errors. It is simply changing one error term while holding the others constant when the errors are uncorrelated across equations in the system. So, in this study, the impulse response function shows the response of PKK-induced violence to a one standard deviation increase/shock (over the error term) in the incapacitated PKK members.

2. Results are statistically significant where both error lines (dashed lines) are away (either above or below) from the zero line indicating 0.95 confidence level. In this case, it is above in the sixth period for the GOVDAT and above in the fourth period for the INSDAT. This includes “0” in the third month. The results are statistically significant..

3. To plot the results for all the analyses, the author used E-views 5.1, a multiple time series analysis software package.

Additional information

Notes on contributors

Mustafa Coşar Ünal

Mustafa Coşar Ünal is an Adjunct Associate Professor at Bilkent University. He received his Ph.D. in 2009 in Public Policy and Administration from the University of Maryland. He served for sixteen years in the Turkish Intelligence Department and held different managerial positions in which he dealt with strategic level analyses of terrorism and insurgency. His research is mostly on terrorism and other types of asymmetric conflict, conflict management and resolution, insurgency, counterinsurgency (COIN), counterterrorism (CT), COIN doctrines and strategies, intelligence, and national security. His recent publications include Counterterrorism in Turkey: Policy Choices and Policy Effects toward the Kurdistan Workers’ Party (PKK) (Routledge); “Opening a Door for Return to Home: Impact and Effectiveness of Turkish Repentance Laws as a Counterterrorism Measure,” in Studies in Conflict and Terrorism; “Strategist or Pragmatist: A Challenging Look at Ocalan's Retrospective Classification and Definition of PKK's Strategic Periods of 1973–2012,” in Terrorism & Political Violence; “The Kurdistan Workers’ Party (PKK) and Popular Support: Counterterrorism towards an insurgency nature,” in Small Wars & Insurgencies; “Terrorist or Insurgency: A Conceptual Analysis,” in Crime, Law and Social Change; “Counterinsurgency and Military Strategy: An analysis of Turkish Army's COIN Doctrines/Strategies,” in Military Operations Research; “Is it Ripe Yet? Resolving Turkey's 30 Years of Conflict With the PKK” in Turkish Studies; and “Do Terrorists Make a Difference in Criminal Networks?” in Social Networks.

Petra Cafnik Uludağ

Petra Cafnik Uludağ is an Adjunct Instructor at Bilkent University and TED University in Ankara. She received her Ph.D. in 2017 in Political Science from Bilkent University. In her research she is focusing on the interaction of media and politics, discursive practices, conceptual history, social movements and terrorism. Her recent publications include “Beware the Winter is Coming! Arab Spring in the Global Media” in Critical Studies in Media Communication and “Insisting on Victory” with Mustafa Coşar Ünal in Revista Científica General José María Córdova.