From the Becker-Posner Blog:
As Posner and others have indicated, there appears to have been a huge conversion of economists toward Keynesian deficit spenders, but the evidence that produced such a "conversion" is not apparent (although maybe most economists were closet Keynesians all along). This is a serious recession, but Romer and Bernstein project a peak unemployment rate without the stimulus of about 9%. The 1981-82 recession had a peak unemployment rate of about 10.5%, but there was no apparent major "conversion" of economists at that time. What is so different about the present recession compared to that one, and to other recessions since then, that would greatly raise the estimated stimulating effects of government spending on various types of goods and services?
But it is not obvious why this should lead to greater confidence in the power of government spending stimulus packages. Of course, perhaps the prior emphasis on crowding out, and skepticism toward the stimulating effects of government spending, were wrong, or that recessions were too short and mild after the 1981-82 recession to call for Keynesian-type stimulus packages.