From WTO-Centered Governance to a Layered Trade Architecture: Functional Allocation Across Institutional Venues, 2000–2025

Global trade governance is being reshaped as multilateral rulemaking and dispute settlement face persistent constraints. However, it remains unclear whether this development signals institutional decline or a layered allocation of governance functions across interconnected venues. This study develops a functional-allocation framework and examines rulemaking, enforcement, and coordination across the World Trade Organization (WTO), WTO-linked mechanisms, and regional trade agreements (RTAs). The framework distinguishes directly observable functional allocation from functional reallocation as a process-oriented interpretation of institutional change. The analysis combines a mapping of 282 RTA governance events entering into force between 2000 and 2025 with treaty content and institutional design data and a structured comparison of WTO core agreements, differentiated arrangements, enforcement supplements, and plurilateral initiatives. The findings identify a layered trade architecture rather than a simple shift away from the WTO. The WTO retains selected multilateral functions, differentiated arrangements sustain selective cooperation within its framework, and WTO-linked mechanisms supplement constrained appellate enforcement. RTAs provide additional venues for rulemaking, enforcement, and coordination. Among directly classified RTA events, formal adjudication increased from 76.0% in 2000–2004 to 100.0% in 2020–2025. Formal adjudication and institutionalized coordination are also positively associated with core substantive treaty depth. These patterns are consistent with functional allocation across a layered architecture, but do not establish that WTO constraints caused the observed institutional configurations.