Can government policies that increase the monopoly power of firms and the militancy of unions increase output? This paper shows that the answer is yes under certain “emergency” conditions. These emergency conditions—zero interest rates and deflation—were satisfied during the Great Depression in the United States. The New Deal, which facilitated monopolies and union militancy, was therefore expansionary in the model presented. This conclusion is contrary to a large previous literature. The main reason for this divergence is that this paper incorporates rigid prices and the zero bound on the short-term interest rate. JEL: E23, E32, E52, E62, J51, N12, N42

In this article we present a simple new Keynesian–style model of debt-driven slumps—that is, situations in which an overhang of debt on the part of some agents, who are forced into rapid deleveraging, is depressing aggregate demand. Making some agents debt-constrained is a surprisingly powerful assumption. Fisherian debt deflation, the possibility of a liquidity trap, the paradox of thrift and toil, a Keynesian-type multiplier, and a rationale for expansionary fiscal policy all emerge naturally from the model. We argue that this approach sheds considerable light both on current economic difficulties and on historical episodes, including Japan’s lost decade (now in its 18th year) and the Great Depression itself.