Of course, for this to work the "money" that's demanded has to be the same as the "money" that the central bank supplies, which requires a particular, and now largely vanished, kind of financial structure, as we've been discussing below. But that's not what I want to talk about here. Rather, it's this other bit:
This time the Fed did all that Friedman denounced it for not doing in the 1930s. The fact that this wasn’t enough amounts to a refutation of Friedman’s claim that adequate Fed action could have prevented the Depression.Do we think this is right? It doesn't seem right to me. If unemployment in the 1930s had peaked at below 10%, instead of 25%; if industrial production had fallen by one eighth, instead of by over half; if fixed investment had fallen by 20%, instead of by 80% (yes, business investment halted almost entirely in the early 30s); if we'd had one or two quarters of deflation, instead of four years; -- then I think we would say that the Depression had indeed been prevented. Krugman is implicitly assuming here today's economy couldn't collapse the way it did in the 1930s, but how do we know that's true?
We always ask, why was the Great Recession so deep? But you could just as well turn the question around and ask why, despite initial appearances, did it turn out to be not nearly as deep as the Depression?
I can think of four families of answers. One is the one that Krugman is implicitly rejecting -- that policy was better this time. I think most people who tell this story -- including some on the left -- would emphasize the rescue of the banking system. Disgusting as it is to see the same smug assholes who caused the crisis handed truckloads of money, if nature had taken its course and the big banks had been allowed to fail, we might really have had a Depression. That's one story. You might also mention fiscal policy, which, while inadequate, has clearly helped, but it's hard to see that explaining more than a few points of the difference.
The second answer would be that the sheer size of government makes a Depression-scale collapse of demand impossible, regardless of policy. In 1929, with government final demand only a couple percent of GDP, autonomous spending basically was investment spending, especially if we think at the global level so exports wash out. Today, by contrast, G is significantly larger than I (about 20 vs 15 percent of GDP), so even if private investment had collapsed at the same scale as in 1929-1933, the percentage fall in autonomous demand would have been much less. (And of course that fact alone helped keep private investment from collapsing.) Interestingly, despite Hyman Minsky's association with stories about finance, this, and not anything to do with the financial system, was why his answer to the question Can "It" Happen Again was, No. Policy is secondary; big government itself is the ballast that stabilizes the economy.
Third would be that the shock in 1929 was greater than the shock in 2007. Of course that would require that you specify the shock, and assumes that you think the causes of the crises were basically exogenous. We could compare a story of the 1920s about radically changed trade patterns as a result of WWI, or about the transition agriculture to industry, to a story for the more recent crisis about the housing bubble, or global imbalances, or the transition from industry to services. If you believe a story like that, there's no reason you couldn't argue that their exogenous shock was bigger than our exogenous shock, and that's the real difference.
Last, you could argue that private demand is inherently more stable today than it was before WWII. Price stickiness, say, usually cast as a villain in macroeconomic stories, could have prevented outright deflation; and greater debt-financing of consumption, again usually seen as part of the problem, could have helped stabilize consumption demand in the face of falling incomes. Or financial markets are less subject to short-term fluctuations in sentiment. (Haha. I crack myself up.)
Personally, I would lean toward door number two. But the important thing is just to reframe the question -- not why was the recession so bad, but why wasn't it worse? If someone ever did an IGM-style survey of economists, but of the good guys, it would be a good thing to ask.