The White House economist takes to the pages of that other Economist to warn against proclaiming victory prematurely. As a lot of commentators have worried about backing into a 1937-type scenario, in which we go off our meds too soon and suffer a relapse, it's especially comforting that 1937 weighs on her mind:

[T]he recovery in the four years after Franklin Roosevelt took office in 1933 was incredibly rapid. Annual real GDP growth averaged over 9%. Unemployment fell from 25% to 14%. The second world war aside, the United States has never experienced such sustained, rapid growth.

However, that growth was halted by a second severe downturn in 1937-38, when unemployment surged again to 19% (see chart). The fundamental cause of this second recession was an unfortunate, and largely inadvertent, switch to contractionary fiscal and monetary policy. ...

Also important was an accidental switch to contractionary monetary policy. In 1936 the Federal Reserve began to worry about its “exit strategy”. After several years of relatively loose monetary policy, American banks were holding large quantities of reserves in excess of their legislated requirements. Monetary policymakers feared these excess reserves would make it difficult to tighten if inflation developed or if “speculative excess” began again on Wall Street. In July 1936 the Fed’s board of governors stated that existing excess reserves could “create an injurious credit expansion” and that it had “decided to lock up” those excess reserves “as a measure of prevention”. The Fed then doubled reserve requirements in a series of steps. Unfortunately it turned out that banks, still nervous after the financial panics of the early 1930s, wanted to hold excess reserves as a cushion. When that excess was legislated away, they scrambled to replace it by reducing lending. According to a classic study of the Depression by Milton Friedman and Anna Schwartz, the resulting monetary contraction was a central cause of the 1937-38 recession. ...

The excess reserves argument is, of course, one you hear increasingly these days.

For what it's worth, Brad DeLong isn't quite so reassured. Writing in response to Romer, he argues that even staying the course on the stimulus that's out there, to say nothing of reversing course prematurely, is likely to fall short:

Six months ago a net federal fiscal stimulus of about $1 trillion--$400 billion each year for about 2.5 years--seemed appropriate: that seemed to balance the benefits of filling-in the hole in aggregate demand without running too great a risk of triggering worrisome inflationary fever further down the road. Now the hole in aggregate demand is greater than was thought likely last December--about twice as great--and the likelihood of heightened future inflation is less. Thus if it was appropriate to set a $1 trillion federal fiscal stimulus in motion last December given what we knew then, if we had known then what we know now it would have been appropriate to set a roughly $2.4 trillion fiscal stimulus--$800 billion for 3 years--in motion back then. ...

[T]he need for federal-level fiscal expansion is reinforced by what state governments are doing right now. The federal government's discretionary actions are expanding aggregate demand by about $400 billion over fiscal year 2010, but state governments are right now cutting their spending and raising their taxes in order to offset this federal fiscal expansion more or less completely. On net, the government sector will be on autopilot as far as discretionary policy moves to stimulate the economy are concerned: federal-level expansion is offset and neutralized by state-level fiscal contraction. This is not an appropriate macroeconomic policy stance: this is the largest economic downturn since the Great Depression. 

You periodically here vague murmurs of additional stimulus plans emanating from the White House, but nothing very concrete. I wonder what would prompt a serious discussion. While DeLong's numbers focus the mind, the legislative calendar is pretty full as it is. What do you ditch to make another stimulus push?

--Noam Scheiber