THE ECONOMICS OF THE GOVERNMENT BUDGET CONSTRAINT

This article summarizes the simple analytics of the macroeconomiceffects of government budget deficits. The presentation is organizedaround three key relationships: the national income accountsbudget deficit identity, the deficit financing identity, andthe dynamic equation for the evolution of the ratio of publicdebt to gross national product. The national income accountsidentity highlights the effect of the deficit on domestic savingand investment and the current account. Examining the financingof the deficit brings to light the different kinds of macroeconomicimbalance the deficit can cause—as a first approximation,printing money excessively shows up as inflation, excessiveuse of foreign reserves leads to crises in the balance of payments,high foreign borrowing leads to a debt crisis, and too muchdomestic borrowing leads to high real interest rates and crowdingout of private investment. The debt dynamics equation is usedto show the long-run constraints on fiscal policy.