This book investigates the paradoxical role of the European Commission as both the enforcer of European Union law and a political actor that selectively tolerates member state noncompliance. Yaning Zhang examines the institutional constraints and political motivations that lead the Commission to adopt inconsistent enforcement strategies. By analyzing legal frameworks alongside political bargaining, the author argues that the Commission's behavior is dictated by a complex interplay of institutional self-interest and the need to maintain political legitimacy within the Union.

Experts in European law and political science recognize this work as a significant contribution to the study of EU institutional behavior. Readers frequently note the academic density of the prose, which is well-suited for scholars and practitioners interested in the mechanics of European integration.