Arnold Kling and I have been discussing what an incredible counterexample to the Keynesian model the post-WWII years are. It occurred to me to check what Keynesians were predicting would happen after the war ended. Here's one of them:
When this war comes to an end, more than one out of every two workers will depend directly or indirectly upon military orders. We shall have some 10 million service men to throw on the labor market. [DRH comment: he nailed that number.] We shall have to face a difficult reconversion period during which current goods cannot be produced and layoffs may be great. Nor will the technical necessity for reconversion necessarily generate much investment outlay in the critical period under discussion whatever its later potentialities. The final conclusion to be drawn from our experience at the end of the last war is inescapable--were the war to end suddenly within the next 6 months, were we again planning to wind up our war effort in the greatest haste, to demobilize our armed forces, to liquidate price controls, to shift from astronomical deficits to even the large deficits of the thirties--then there would be ushered in the greatest period of unemployment and industrial dislocation which any economy has ever faced. [italics in original]
This is from Paul Samuelson, "Full Employment after the War," in S.E. Harris, ed., Postwar Economic Problems, 1943.
It's true that the war ended about two years after he wrote, rather than six months, but that would probably have made his prediction even more extreme. But pretty much everything else he speculated about policywise happened: the huge drop in the deficit, the end of price controls, and the demobilization.
It's also true that he said "Of course, this is not intended as a picture of what will in fact happen." But look at what he wrote directly after this quoted sentence to explain why things might work out better than he provisionally predicted:
For there is every reason to believe that we shall not be lulled into a feeling of false security by the last war's experience or by the half-truth that the end of the war will witness a boom. No doubt, we shall retain direct controls for a period after the conflict ends. We shall taper off war production gradually. We shall undertake income maintenance in the form of dismissal pay for soldiers, unemployment compensation, direct and work relief expenditure. It is probable, although less certain, that, in addition, the Federal government will initiate employment maintenance measures such as large scale public works, etc. But even these will not be adequate to maintain full employment or any approach to it.
Of course, direct controls were removed relatively quickly, certainly within a year and a half of the end of the war. War production did not taper off gradually but plunged. I don't think there was any dismissal pay for soldiers. You could see the GI Bill as a form of relief expenditure, but if I recall correctly, at any given time only about 500,000 people were taking advantage of the GI Bill to get education. And there were no large scale public works programs.
Here's what I wrote about the post WWII episode in a forthcoming piece on Canada's budget turnaround between 1994 and 2006:
This reinforces the lesson from the far more extreme U.S. experience after World War II: Between FY 1945 and FY 1947, federal government spending was cut by 61 percent. This was a 27-percentage-point drop from 41.9 percent of GDP to 14.7 percent of GDP. Yet the unemployment rate over that same time rose from 1.9 percent to only 3.6 percent. The postwar bust that so many Keynesians expected to happen never did.