An extended counter-argument emerges from these blog posts: http://krugman.blogs.nytimes.com/2012/06/06/think-of-the-chi... http://krugman.blogs.nytimes.com/2012/06/06/doing-their-best... http://krugman.blogs.nytimes.com/2012/04/15/insane-in-spain/
Given Krugman's little rant on Sweden http://krugman.blogs.nytimes.com/2012/05/16/sweden-sweden-as... which spawned responses like http://www.tomwoods.com/blog/sweden-no-longer-the-free-marke... and his attitude towards Estonia and the US stimuli, I think there is some doubt as to his work.
I am of no fixed opinion when it comes to economic theory, but Krugman's and Dean Baker's writings on the economy of the last ten years (i.e. housing bubble onwards) are some of the few things I've found that are intended for a general audience, are (at least partly) based on data rather than ideology alone, and seem coherent to me. That doesn't mean they're right, of course. If there's a critique of their view that meets the same criteria – generally accessible, based on evidence, not entirely ideological, and coherent – I'd like to see it. Most of what I've run across in that department is either incomprehensible to me, obviously ideological, or both.
The people who seem lacking in credibility right now are the ones recommending plunging ahead with full-bore austerity when there are both obvious reasons to think it will make matters worse (because it will reduce demand and slow growth) and obvious evidence that it is doing so right now, e.g. in the UK, which has been running this experiment for the last few years. Perhaps this is just my ignorance speaking, but what I noticed is: (1) those austerity measures were greeted by loud cheers by the same people who still think that way today; (2) the Krugman and Baker types predicted that it would make things worse; (3) the UK has gone back into recession.