This paper examines how the mass return of refugees can shape conflict dynamics in their home communities. It focuses on the large-scale repatriation of Afghan refugees following the sudden reintroduction of “Maximum Pressure” sanctions on Iran in 2018, which severely weakened Iran’s economy and spurred the return of over 600,000 Afghans.
The study uses a quasi-experimental difference-in-differences design to isolate the causal effect of repatriation on violence. It exploits historical settlement patterns of Afghan returnees from Iran between 2012 and 2015 to measure districts’ prior exposure to return, and leverages the unexpected timing of the 2018 sanctions as a common shock. By comparing changes before and after sanctions across districts with high versus low prior exposure, the authors estimate the impact of the repatriation shock on conflict outcomes over 2016–2018 at the district level.
The analysis draws on multiple data sources to measure conflict, returns, and local conditions. Unclassified military conflict records from the International Distributed Unified Reporting Environment (INDURE) for 2016–2018 provide georeferenced data on insurgent-initiated attacks against Afghan security forces and NATO partners. District-level repatriation data from IOM’s Baseline Mobility Assessment capture the spatial distribution and intensity of returns, and the Asia Foundation’s Survey of Afghan Returnees (SAR) helps triangulate motives for return and track social dynamics within communities receiving returnees.
Main findings:
- The sanctions-induced mass return increased insurgent violence in return communities. A one-standard-deviation increase in the share of returnees is associated with a 1.5-2.5 percentage point rise in the probability of insurgent conflict and an increase of 0.7-1.5 attacks per 100,000 residents. These effects point to a measurable deterioration in security in areas most exposed to the repatriation shock.
- The return did not heighten communal tensions between returnees and non-migrants. Returnees driven home by sanctions reported modestly better relations and were 3.6-4 percentage points less likely to experience violent communal disputes. This suggests that the rise in violence is not primarily driven by local social conflict between returnees and host communities.
- Economic hardship linked to return likely lowered the opportunity cost of insurgent recruitment. Return-exposed districts saw declines in full-time employment, labor market satisfaction, food security, and nighttime luminosity, consistent with deteriorating economic conditions. These patterns align with reduced remittances and trade due to sanctions and a local labor supply shock, which together may have lowered reservation wages and increased the pool of potential recruits.
- Insurgents shifted toward more labor-intensive tactics where more returnees settled. A one-standard-deviation increase in exposure was associated with a 1.7 percentage point rise in the share of insurgent attacks that were labor-intensive, including direct fire and complex ambush operations. This tactical shift is consistent with an expanded supply of available fighters in more exposed districts.
- Iran’s retaliatory behavior likely amplified violence in affected Afghan districts. Violence rose more sharply in areas with pre-existing links to Iranian covert support networks, indicating that sanctioned states may escalate support to armed groups. Such strategic responses can compound the security impact of mass refugee returns.
The paper concludes that the impacts of refugee repatriation are highly context-dependent: when returns are triggered by deteriorating host-country conditions—such as the 2018 sanctions on Iran—they can inadvertently heighten insurgent violence by enlarging the pool of potential recruits. It highlights a cross-border security externality of economic sanctions and other policies that induce involuntary returns: by weakening host economies and disrupting remittances and trade, these shocks can depress local conditions in origin communities, lower the opportunity cost of recruitment into armed groups, and—where external support networks are active—contribute to further escalation.