- The stimulus package couldn’t have been successful because the bulk of it hasn’t even been spent yet. (Perhaps represented by this type of article: http://www.cnsnews.com/news/article/57617)
- The Ricardian equivalence argument that every dollar of stimulus spent by the government dissuades a dollar of private investment because people rationally believe that the government’s spending will necessitate future tax increases. That anticipation causes people to save more to finance the future spending. (This seems in line with John Cochrane in his recent New Yorker interview, here: http://www.newyorker.com/online/blogs/johncassidy/2010/01/interview-with-john-cochrane.html.)
I don’t know if people rationally anticipate future inflows and outflows or if they don’t. The cheap answer (but one that’s probably right) is that they do sometimes or to some degree. But if you’re trying to make a logical economic argument for why the stimulus couldn't have worked (rather than an empirical stab at measuring whether it *did* work), it’s a cheap argument to say that people sometimes anticipate the future and sometimes don’t. If you have to hold or drop your belief about rationality depending on how well the implications fit your priors, that’s a bad sign.