What I mean by the title of this post is that the central-bank tightening that almost always precedes an economic bust is never the cause of the bust. However, it’s a fact that economic busts are indirectly caused by policy mistakes, in that policy mistakes lead to artificial, credit-fueled booms. Once such a boom has been fostered, an ensuing and painful economic bust becomes unavoidable. The only question is: will the bust be short and sharp (the result if government and its agents stay out of the way) or drag on for more than a decade (the result if the government and its agents try to boost “aggregate demand”)?

The most commonly cited historical case of a policy mistake directly causing an economic bust is the Fed’s gentle tap on the monetary brake in 1937. This ‘tap’ was quickly followed by the resumption of the Great Depression, leading to the superficial conclusion that the 1937-1938 collapse in economic activity would never have happened if only the Fed had remained accommodative.

Let’s now take a look at what actually happened in 1937-1938 that could have caused the economic recovery of 1933-1936 to rapidly and completely disintegrate.

First, while commercial bank assets temporarily stopped growing in 1937, they didn’t contract. Commercial bank assets essentially flat-lined during 1937-1938 before resuming their upward trend in 1939.

Second, outstanding loans by US commercial banks were roughly the same in 1938 as they had been in 1936, so there was no widespread calling-in of existing loans. That is, there was no commercial-bank credit contraction to blame for the economic contraction.

Third, the volume of money held by the public was higher in 1937 than in 1936 and was roughly the same in 1938 as in 1937.

Fourth, M1 and M2 money supplies were roughly unchanged over 1937-1938, so there was no monetary contraction.

Fifth, the consolidated balance sheet of the Federal Reserve system was slightly larger in 1937 than in 1936 and significantly larger in 1938 than in 1937, so there was no genuine tightening of monetary conditions by the Fed at the time.

Sixth, an upward trend in commercial bank reserves that began in 1934 continued during 1937-1938.

Seventh, there were no increases in the interest rates set by the Fed during 1937-1938. In fact, there was a small CUT in the FRBNY’s discount rate in late-1937.

What, then, did the Fed do that supposedly caused one of the steepest economic downturns in US history? The answer is that it boosted commercial-bank reserve requirements.

All of which prompts the question: How did a 1937 increase in reserve requirements that didn’t even lead to a monetary or credit contraction possibly cause manufacturing activity to collapse and unemployment to skyrocket?

It’s a trick question, because the increase in reserve requirements clearly didn’t cause any such thing. The economic collapse of 1937-1938 happened because the recovery of 1933-1936 was not genuine, but was, instead, an artifact of increased government spending and other attempts to prop-up prices. The economy had never been permitted to fully eliminate the imbalances that arose during the late-1920s, so a return to the worst levels of the early-1930s was inevitable.

Many analysts are now worrying out loud that the Fed will repeat the so-called “mistake of 1937″, but the real problem is that the Fed and the government repeated the policy mistakes of the late-1920s and then repeated the policy mistakes of 1930-1936. The damage has been done and another economic bust is now unavoidable, regardless of what the Fed decides at this week’s meeting.