The Importance of Keynesian Thought Today: Systemic Crises, Institutional Expectations, Unconventional Policy, and the Transition toward an Expanded Keynesianism (Demand and Supply)

This paper reassesses the relevance of Keynesian thought as a theory of systemic crises rather than mere cyclical fluctuations. Building on a historical-comparative framework (Great Depression, 2008 financial crisis, and the 2020 pandemic), it argues that modern macroeconomic instability cannot be explained by rational expectations models nor by behavioral irrationality alone. Instead, crises emerge from the interaction between effective demand, the credit channel, and institutional expectations regarding crisis-management capacity. The article proposes a “modified Keynesianism” integrating five core components: effective demand, financial intermediation, institutional expectations, policy coordination, and unconventional monetary policy (QE/LSAP). Additionally, it introduces the need for short-term supply-side macro tools to address real shocks, extending Keynesian theory toward what is termed Supply Side Keynesianism. The contribution lies in offering a unified framework for understanding and managing large-scale disequilibria in contemporary economies, where institutional credibility and coordinated intervention are central to restoring stability and growth.