The late 1960s through 1989 period saw a consolidation of liberal institutionalist explanations emphasizing the role of international organizations in shaping cooperation, while increasingly acknowledging domestic political constraints. Researchers pursued models that connect domestic ratification, electoral incentives, and policy preferences to treaty design and compliance, using game-theoretic and regime-analysis tools to explain when institutions can reduce coordination costs. There was also a notable expansion into cognitive and organizational dimensions of institutions, treating memory, classification, and identity as active shapers of state behavior and memory of past interactions. These strands converge on governance and integration, with a focus on joint-decision dynamics and the bottlenecks that shape regional and global governance.