"Because most periods of economic weakness are fairly short-lived, it is generally preferable that stimulus policies be short-lived. Currently, however, CBO projects that economic output will remain significantly below its potential for several more years, so policies that provide stimulus for an extended period of time may be appropriate. Indeed, a fiscal stimulus that ends before the economy has started to regain its footing runs the risk of exacerbating economic weakness when the stimulus ends."
So he, at least, seems to think that spending in FY 2011 will not be wasted. The chart above shows why.