In today's Wall Street Journal, top economist Robert Barro has an important essay on why so-called "stimulus" spending really is a drag on economies. It's must-reading for anyone opposed in principle to wasteful liberal spending passed off as some magic Keynesian pill:
Every time heightened fiscal deficits fail to produce desirable outcomes, the policy advice is to choose still larger deficits. If, as I believe to be true, fiscal deficits have only a short-run expansionary impact on growth and then become negative, the results from following this policy advice are persistently low economic growth and an exploding ratio of public debt to GDP.
The last conclusion is not just academic, because it fits with the behavior of Japan over the past two decades. Once a comparatively low public-debt nation, Japan apparently bought the Keynesian message many years ago. The consequence for today is a ratio of government debt to GDP around 210%—the largest in the world.
This vast fiscal expansion didn't avoid two decades of sluggish GDP growth, which averaged less than 1% per year from 1991 to 2011. No doubt, a committed Keynesian would say that Japanese growth would have been even lower without the extraordinary fiscal stimulus—but a little evidence would be nice.
Despite the lack of evidence, it is remarkable how much allegiance the Keynesian approach receives from policy makers and economists. I think it's because the Keynesian model addresses important macroeconomic policy issues and is pedagogically beautiful, no doubt reflecting the genius of Keynes. The basic model—government steps in to spend when others won't—can be presented readily to one's mother, who is then likely to buy the conclusions.
Keynes worshipers' faith in this model has actually been strengthened by the Great Recession and the associated financial crisis. Yet the empirical support for all this is astonishingly thin. The Keynesian model asks one to turn economic common sense on its head in many ways. For instance, more saving is bad because of the resultant drop in consumer demand, and higher productivity is bad because the increased supply of goods tends to lower the price level, thereby raising the real value of debt. Meanwhile, transfer payments that subsidize unemployment are supposed to lower unemployment, and more government spending is good even if it goes to wasteful projects.
There's much more in the editorial, definitely worth reading and bookmarking.