Greg Mankiw’s Blog: Smoot-Hawley Revisited
One general lesson from his discussion is that it is often hard to distinguish shocks to aggregate supply and shocks to aggregate demand. Policies and events that adversely affect aggregate supply (e.g., trade restrictions) will often reduce the marginal productivity of capital, decrease investment spending for given interest rates, and depress aggregate demand as well. In the short run, the indirect demand-side effects of “supply shocks” could potentially be larger than the direct supply-side effects.