大不況は再来するか
●Gregory Mankiw, “But Have We Learned Enough?”（New York Times, October 25, 2008）
But when Olivier Blanchard, the I.M.F.’s chief economist, was asked about the possibility of the world sinking into another Great Depression, he reassuringly replied that the chance was “nearly nil.” He added, “We’ve learned a few things in 80 years.”
LOOKING back at these events, it’s hard to avoid seeing parallels to the current situation. Today, as then, uncertainty has consumers spooked. By some measures, stock market volatility in recent days has reached levels not seen since the 1930s. With volatility spiking, the University of Michigan’s survey reading of consumer sentiment has been plunging.
Deflation across the economy is not a problem (yet), but deflation in the housing market is the source of many of our present difficulties. With so many homeowners owing more on their mortgages than their houses are worth, default is an unfortunate but often rational choice. Widespread foreclosures, however, only perpetuate the downward spiral of housing prices, further defaults and additional losses at financial institutions.
The Fed and the Treasury Department, intent on avoiding the early policy inaction that let the Depression unfold, have been working hard to keep credit flowing. But the financial situation they face is, arguably, more difficult than that of the 1930s. Then, the problem was largely a crisis of confidence and a shortage of liquidity. Today, the problem may be more a shortage of solvency, which is harder to solve.
Let me be clear: Like Mr. Blanchard at the I.M.F., I am not predicting another Great Depression. We have indeed learned a lot over the last 80 years. But you should take that economic forecast, like all others, with more than a single grain of salt.
今般の金融危機と1930年代の大不況（Great Depression）との推移が類似していることもあって、「すわっ！ 大不況の再来か」と悲観的になってしまうのも無理はない。私（＝マンキュー）はブランシャールと同じく1930年代並みの不況が再来することはないだろうと予測するけれども、経済学者の予測を過度に信頼するのも考えものだよ、とのこと。
1930年代の大不況時のように政府（中央銀行含む）が事態をさらに悪化させる（あるいは不況を後押しする）ようなことはないだろう（＝例えば不況期に非効率的な企業を市場から退出させることを目的として政府予算の縮小・金融引き締めが実施されるようなことはないだろう）、とどこの馬の骨ともわからない私は予測しますが*1、この予測は自分で言うのもなんだけど信じないほうがいいと思う。というのも、何もしないことが時に不況の深化に手を貸すことになるとすれば（積極的な景気悪化の原因とまではいえないかもしれないけれども）、某極東の島国においてすでにこの予測は外れてるような気がしないでもないから。
