In the battle against the economic impact of COVID-19, governments around the world are pulling out all the stops. In advanced economies, leading central banks have pushed interest rates to zero or below. And, a recent IMF estimate puts the combination of discretionary spending and automatic fiscal stabilizers (including unemployment insurance and progressive income taxation) at $9 trillion―more than 10 percent of global GDP.

With bond yields low or negative, the limits to monetary policy are clear (see our pre-COVID post). How large is the scope for additional countercyclical fiscal policy? With sovereign yields so low, the cost of additional financial expansion looks to be minimal, at least for now (see, for example, Blanchard).

Nevertheless, each time public debt-to-GDP ratios ratchet higher—as they did in the 2007-09 crisis and are now doing again—the question of “fiscal space” reemerges. When the next economic shock hits, will governments again be able to provide relief and stimulus on the scale required to meet society’s needs?

In this post, we highlight recent fiscal developments in advanced economies, and review the factors affecting the sustainability of their high and rising levels of debt. To foreshadow our conclusion, the fact that many countries’ fiscal positions were precarious even before the COVID crisis does not weaken the current case for stimulus. But, doubts about fiscal space are growing. So, it is important that governments find a way to make a credible commitment to future fiscal consolidation when their economies have returned to full employment. Failure to do so could threaten confidence both in government finances and in economic performance….