Of course it will be contested hotly by the right, but quite an array of economists, local and international, and find that "fiscal policy does in fact work when it's not offset by monetary policy."
Krugman points to DeLong who in turn points to David Romer. Here's Romer via DeLong:
... There has been a great deal of new research that sheds light on the effects of fiscal policy in settings where monetary policy does not respond aggressively. Some of it uses evidence from the crisis itself, but much does not; some focuses on a particular country, usually the United States, but some uses larger samples; and a considerable body of the work looks at evidence from different regions within a country, again usually the United States. One particularly appealing aspect of this last set of studies is that because monetary policy is conducted at the national level, it is inherently being held constant when one is looking at within-country variation.
Collectively, this research points very strongly (though, I should say, not unanimously) to the conclusion that when monetary policy does not respond, conventional fiscal stimulus is effective. And a careful examination of the evidence gives no support to the view that when monetary policy is constrained, fiscal contractions are expansionary (International Monetary Fund, 2010). Even so, I find two types of evidence that predate the crisis even more compelling. The first comes from wars. The fact that the major increases in government purchases in the two world wars and the Korean War were associated with booms in economic activity, and that those booms occurred despite very large tax increases and extensive microeconomic interventions whose purpose was to restrict private demand, seems to me overwhelming evidence that fiscal stimulus matters.
Maybe we can thank the right for being so wrong during such a damaging time that bunches of economists went deep into the data and got the answers. I'm at the pre-elementary level when it comes to economics, but this stuff seemed obvious from the beginning.
Now, Christmas good will to the contrary notwithstanding, I'd just as soon the right drowned in its own spittle. Too many people for too long have been paying heavily for the decision by some danged editor at whatever publishing house to make Ayn Rand widely available to half-wits.
