- Christopher Blair University of Pennsylvania
Where cross-border sanctuary enables rebels to marshal external support, classical theories of counterinsurgency extol the strategic value of border control. By sealing borders, counterinsurgents can erode transnational rebels’ resources, degrading the quality of rebellion. Building on theories linking resources and technologies of rebellion, I posit a fortification dilemma inherent in border control strategies. Well-resourced rebels with external support can afford conventional attacks and indiscriminate violence. When counterinsurgent border control efforts interdict foreign logistics, insurgents compensate by cultivating greater local support. In turn, rebels prefer more irregular attacks and reduced civilian victimization. Because counterinsurgent border control efforts tradeoff reduced insurgent capabilities for greater competition over local hearts-and-minds, border control is best used in tandem with population-centric counterinsurgency. I illustrate this theory with archival evidence from the Algerian War of Independence, and test it using declassified microdata on border fortification and violence in a difference-in-differences setting in Iraq.