The deportation of irregular migrants is a burning issue in public debates all around the world. Most states invest heavily in effective deportation regimes, but when it comes to implementation, deportation regimes are notorious for not achieving their declared goals. Everywhere, marked discrepancies persist between deportation policies and actual practices of deportation.This project compares the implementation of deportation regimes in four different states – Israel, Greece, Spain and Ecuador – in order to provide a closely researched assessment of implementation practices. It interrogates a core assumption in much of the scholarly literature on the “deportation turn”, namely, that there is a global convergence of state deportation regimes.The project adds a crucial – yet, so far underexplored – perspective on irregular migration: the interface of street-level state agents and civil-society actors in shaping practices of deportation. Existing studies look either at the “top level” of the state (policies, laws, procedures, etc.), or at the “underground level” of its “victims” (irregular migrants’ survival strategies, trafficking networks, etc.). This project privileges the “meso level” of the deportation regime, bringing to light the agency of those who exercise discretion in interpreting laws and policies at the “implementation interface”. It makes an original contribution to the anthropology of the state, by demonstrating that the territorial sovereignty of states is constantly renegotiated at this level.The project will produce knowledge on the dilemmas, tactics and occasional alliances of those who carry out and those who obstruct deportation regimes. It will provide new insights into actors’ motivations and worldviews, and explore the dynamics of both “implementation deficits” and “implementation surpluses”. The fine-grained comparative methodology is aimed at producing findings that will be of theoretical significance and of vital importance for policymakers, street-level agents and civil-society actors in dealing with the realities of irregular migration in the 21st century.