YSEC Yearbook of Socio-Economic Constitutions 2025

This volume of the Yearbook of Socio-Economic Constitutions (YSEC) examines the growing importance of domestic legal systems in contemporary international investment law. Long structured primarily around bilateral investment treaties (BITs) and free trade agreements (FTAs), the regulation of foreign investment is undergoing a significant transformation as states reclaim regulatory authority and redefine the relationship between international commitments and domestic law. A central feature of this development is the rapid expansion of foreign investment screening: once a relatively limited instrument, investment screening has become a major component of contemporary investment governance, particularly in sectors associated with national security, strategic infrastructure, critical technologies, energy, data, and supply-chain resilience. Its rise indicates a broader move towards greater domestic control over the admission, operation, and supervision of foreign investment. The volume adopts a comparative and cross-regional perspective, and explores this changing scenario against the background of treaty termination, new model investment agreements, and the increasing use of exceptions, reservations, and exclusions designed to preserve state regulatory space. The chapters consider how investment governance is being reconfigured through national and regional regimes and through hybrid forms of regulation combining international and domestic norms. The contributions examine the role of constitutional principles and domestic legal rules in areas traditionally governed by international standards; the development of investment screening mechanisms; the scope of investor protection under emerging national and regional frameworks; and the growing range of obligations imposed on foreign investors. They also address the interaction between domestic law and international commitments and its implications for investment arbitration, including the extent to which tribunals must apply, interpret, or defer to domestic laws, regulatory decisions, and public policy choices.