I’ll be frank: the discussion of fiscal stimulus this past year and a half has filled me with despair over the state of the economics profession. If you believe stimulus is a bad idea, fine; but surely the least one could have expected is that opponents would listen, even a bit, to what proponents were saying. In particular, the case for stimulus has always been highly conditional. Fiscal stimulus is what you do only if two conditions are satisfied: high unemployment, so that the proximate risk is deflation, not inflation; and monetary policy constrained by the zero lower bound.

That doesn’t sound like a hard point to grasp. Yet again and again, critics point to examples of increased government spending under conditions nothing like that, and claim that these examples somehow prove something.

Here’s the latest, from Tyler Cowen:

Certainly, in Germany, the recent history of fiscal stimulus wasn’t entirely positive. After reunification in 1990, the German government borrowed and spent huge amounts of money to finance reconstruction and to bring East German living standards up to West German levels. Millions of new consumers were added to the economy. These policies did unify the country politically but were not overwhelmingly successful economically. An initial surge was followed by years of disappointing results for output and employment.

This passage makes me want to stick a pencil in my eye. Let’s consider the case:

1. This was not an effort at fiscal stimulus; it was a supply policy, not a demand policy. The German government wasn’t trying to pump up demand — it was trying to rebuild East German infrastructure to raise the region’s productivity.

2. The West German economy was not suffering from high unemployment — on the contrary, it was running hot, and the Bundesbank feared inflation.

3. The zero lower bound was not a concern. In fact, the Bundesbank was in the process of raising rates to head off inflation risks — the discount rate went from 4 percent in early 1989 to 8.75 percent in the summer of 1992. In part, this rate rise was a deliberate effort to choke off the additional demand created by spending on East Germany, to such an extent that the German mix of deficit spending and tight money is widely blamed for the European exchange rate crises of 1992-1993.

In short, it’s hard to think of a case less suited to tell us anything at all about fiscal stimulus under the conditions we now face. And the fact that a prominent commentator on current events apparently doesn’t know that, after a year and a half of debating this issue — well, as I said, I’m feeling fairly despairing.