Our friend Mario Rizzo has been doing absolutely splendid work uncovering the "real" Keynes and his skepticism about the stimulus value of public works programs. In preparing for this morning's edition of my senior seminar, which covers the Hoover years, I was struck in re-reading Rothbard's chapters on 1929 and 1930 how much support there was among mainstream economists of the era for public works programs as unemployment relievers. I bring this up because this was all very much before Keynes wrote The General Theory. We already know, of course, that Hoover enacted a number of such programs during his time as president.
The pre-GT support for public works gives further lie to the various myths of the Great Depression, especially the one that somehow thinks that Keynesian economics was "behind" the New Deal's massive economic interventionism. In fact, as many have shown, the New Deal was hardly constructed on the basis of a theory of any sort, and even if FDR had turned to Keynes, he would have found a much more ambiguous message (as Mario points out). And, given my morning's reading, the idea of using public works to create employment didn't need Keynes anyway: plenty of big name economists believed it long before FDR became president and there was any such thing as Keynesian economics.
For all the good that economists did in opposing Smoot-Hawley, they did much to undermine it by supporting various public works boondoggles.