Do border walls inhibit the spread of transnational terrorism? Previous research has primarily measured the volume of terrorism without explicitly modeling its diffusion or considering how walls might affect different groups differently. To address these oversights, the study adopts a network-based approach, analyzing the impact of border walls on the spread of violence among 63 extremist organizations from 1970 to 2017. The findings show that barriers generally inhibit diffusion, but their effectiveness varies significantly among groups. This research challenges policymakers who regard walls as a catch-all solution for terrorism, offering a fresh perspective on whether walls’ effects justify their cost.
AlesinaADevleeschauwerAEasterlyW, et al. (2003) Fractionalization. Journal of Economic Growth8: 155–194.
2.
AsalVConradJWhiteP (2014) Going abroad: Transnational solicitation and contention by ethnopolitical organizations. International Organization68(4): 945–978.
3.
AsalVHoffmanAM (2016) Media effects: Do terrorist organizations launch foreign attacks in response to levels of press freedom or press attention?Conflict Management and Peace Science33(4): 381–399.
4.
AsalVHKarl RethemeyerRSchoonEW (2019) Crime, conflict, and the legitimacy trade-off: Explaining variation in insurgents’ participation in crime. The Journal of Politics81(2): 399–410.
5.
AvdanNGelpiCF (2017) Do good fences make good neighbors? Border barriers and the transnational flow of terrorist violence. International Studies Quarterly61(1): 14–27.
6.
AvdanNOmelichevaM (2021) Human trafficking–terrorism nexus: When violent non-state actors engage in the modern-day slavery. Journal of Conflict Resolution65(9): 1576–1606.
7.
BapatNA (2007) The internationalization of terrorist campaigns. Conflict Management and Peace Science24(4): 265–280.
8.
BenedictoARBrunetP (2018) Building Walls: Fear and Securitization in the European Union. Amsterdam: Transnational Institute.
9.
BlairCW (2023) The fortification dilemma: Border control and rebel violence. American Journal of Political Science: 1–20.
10.
BlairCWChenowethEHorowitzMC, et al. (2022) Honor among thieves: Understanding rhetorical and material cooperation among violent nonstate actors. International Organization76(1): 164–203.
BurgoonB (2006) On welfare and terror: Social welfare policies and political-economic roots of terrorism. Journal of Conflict Resolution50(2): 176–203.
13.
BymanD (2005) Deadly Connections: States that Sponsor Terrorism. New York: Cambridge University Press.
14.
CannonB (2016) Terrorists, geopolitics and Kenya’s proposed border wall with Somalia. Contemporary Voices: St Andrews Journal of International Relations7(2): 23–37.
15.
CarlingJ (2007) Migration control and migrant fatalities at the Spanish–African borders. International Migration Review41(2): 316–343.
16.
CarterDBPoastP (2017) Why do states build walls? Political economy, security, and border stability. Journal of Conflict Resolution61(2): 239–270.
17.
CarterDBPoastP (2020) Barriers to trade: How border walls affect trade relations. International Organization74(1): 165–185.
18.
CarterDBSignorinoCS (2010) Back to the future: Modeling time dependence in binary data. Political Analysis18(3): 271–292.
19.
CarterDBYingL (2021) The gravity of transnational terrorism. Journal of Conflict Resolution65(4): 813–849.
20.
ChambersSNBoyceGALauniusS, et al. (2021) Mortality, surveillance and the tertiary “funnel effect” on the US–Mexico border: A geospatial modeling of the geography of deterrence. Journal of Borderlands Studies36(3): 443–468.
21.
ChuTSBraithwaiteA (2017) The impact of foreign fighters on civil conflict outcomes. Research & Politics4(3): 2053168017722059.
22.
CoppedgeMGerringJLindbergSI, et al. (2019) Varieties of Democracy (V-Dem) Project, Varieties of Democracy: Codebook v9. Available from: https://www.v-dem.net/static/website/img/refs/codebookv111.pdf.
23.
Correlates of War Project (2017) State System Membership List, v2016. Available from: http://correlatesofwar.org.
24.
De la CalleLSánchez-CuencaI (2012) Rebels without a territory: An analysis of nonterritorial conflicts in the world, 1970–1997. Journal of Conflict Resolution56(4): 580–603.
25.
Felbab-BrownV (2017) The Wall: The Real Costs of a Barrier between the United States and Mexico. Washington, DC: Brookings Institution Press.
26.
GaibulloevK (2015) Terrorist group location decision: An empirical investigation. Oxford Economic Papers67(1): 21–41.
27.
GaibulloevKSandlerT (2021) Determinants of home-base attacks by terrorist groups. Defence and Peace Economics32(6): 644–663.
28.
GelpiCAvdanN (2018) Democracies at risk? A forecasting analysis of regime type and the risk of terrorist attack. Conflict Management and Peace Science35(1): 18–42.
29.
GetmanskiAGrossmanGWrightAL (2019) Border walls and smuggling spillovers. Quarterly Journal of Political Science. doi:https://doi.org/10.1561/100.00018094.
30.
GiblerDMMillerSVLittleEK (2016) An analysis of the militarized interstate dispute (MID) dataset, 1816–2001. International Studies Quarterly60(4): 719–730.
31.
HainmuellerJMummoloJXuY (2019) How much should we trust estimates from multiplicative interaction models? Simple tools to improve empirical practice. Political Analysis27(2): 163–192.
32.
HassnerREWittenbergJ (2015) Barriers to entry: Who builds fortified boundaries and why?International Security40(1): 157–190.
33.
HendrixCSYoungJK (2014) State capacity and terrorism: A two-dimensional approach. Security Studies23(2): 329–363.
34.
HollifieldJF (2004) The emerging migration state. International Migration Review38(3): 885–912.
35.
HorowitzMCPotterPBK (2014) Allying to kill: Terrorist intergroup cooperation and the consequences for lethality. Journal of Conflict Resolution58(2): 199–225.
36.
HouDGaibulloevKSandlerT (2020) Introducing extended data on terrorist groups (EDTG), 1970 to 2016. Journal of Conflict Resolution64(1): 199–225.
37.
JonesSG (2017) Waging Insurgent Warfare: Lessons from the Vietcong to the Islamic State. Oxford University Press.
38.
KenwickMRSimmonsBAMcAlexanderRJ (2023) Infrastructure and authority at the state’s edge: The Border Crossings of the World Dataset. Journal of Peace Research,00223433221145582.
39.
KriegerTMeierrieksD (2011) What causes terrorism?Public Choice147: 3–27.
40.
LaFreeGXieMMatanockAM (2018) The contagious diffusion of worldwide terrorism: Is it less common than we might think?Studies in Conflict & Terrorism41(4): 261–280.
41.
LindbergSICoppedgeMGerringJ, et al. (2014) V-Dem: A new way to measure democracy. Journal of Democracy25(3): 159–169.
42.
LinebargerCBraithwaiteA (2020) Do walls work? The effectiveness of border barriers in containing the cross-border spread of violent militancy. International Studies Quarterly64(3): 487–498.
43.
LinebargerCBraithwaiteA (2022) Why do leaders build walls? Domestic politics, leader survival, and the fortification of borders. Journal of Conflict Resolution66(4-5): 704–728.
44.
MaletD (2013) Foreign Fighters: Transnational Identity in Civil Conflicts. New York: Oxford University Press.
45.
MiltonDSpencerMFindleyM (2013) Radicalism of the hopeless: Refugee flows and transnational terrorism. International Interactions39(5): 621–645.
46.
PhillipsBJ (2019) Terrorist group rivalries and alliances: Testing competing explanations. Studies in Conflict & Terrorism42(11): 997–1019.
47.
PiazzaJA (2009) Is islamist terrorism more dangerous?: An empirical study of group ideology, organization, and goal structure. Terrorism and Political Violence21(1): 62–88.
48.
PiazzaJA (2011) Poverty, minority economic discrimination, and domestic terrorism. Journal of Peace Research48(3): 339–353.
49.
SalehyanI (2009) Rebels Without Borders: Transnational Insurgencies in World Politics. Ithaca, NY: Cornell University Press.
50.
SalehyanIGleditschKSCunninghamDE (2011) Explaining external support for insurgent groups. International Organization65(4): 709–744.
51.
SchonJLeblangD (2021) Why physical barriers backfire: How immigration enforcement deters return and increases asylum applications. Comparative Political Studies54(14): 2611–2652.
52.
SterlingBL (2009) Do Good Fences Make Good Neighbors?: What History Teaches us About Strategic Barriers and International Security. Washington, DC: Georgetown University Press.
53.
TintiPReitanoT (2018) Migrant, Refugee, Smuggler, Saviour. Oxford: Oxford University Press.
54.
ValenteTWVega YonGG (2020) Diffusion/contagion processes on social networks. Health Education & Behavior47(2): 235–248.
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