Modern Monetary Theory: A Solid Theoretical Foundation of Economic Policy?

This paper shows that so-called modern monetary theory (MMT) lacks a sound economic foundation for its far-reaching policy recommendations. This paper’s main contribution to the literature concerns the theoretical foundation of MMT. A simple macroeconomic model shows that MMT is indistinguishable from the Keynesian cross model, as well as a neoclassical macroeconomic model, even when taking account of money in the sense of MMT. This result is in stark contrast to the claims of MMT proponents. Accordingly, it is asserted that MMT is a fundamentally new theory of money and monetary economics. However, MMT is admittedly based on the functional finance concept of the 1940s and money is modelled as an accounting identity. In addition, the fundamental connection between government expenditures for goods and services and the steady state equilibrium value of the national income, the so-called fiscal stance, is a well-known result that is not only consistent with MMT. The interpretation of the fiscal stance, in combination with the accounting identity for money, is a major issue because an equilibrium condition should have a certain causal direction of effects. Based on this reading of the equilibrium condition, policy recommendations encompass the fiscal dominance of monetary policy via monetization of public debt, a job guarantee by the state, along with a so-called Green New Deal. According to the results of this paper, these policy recommendations cannot be justified with MMT. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11293-021-09713-6.