Bruce Bartlett in Forbes:
If the public works are genuine public goods that add to the nation's capital stock, then it doesn't matter too much if they aren't completed until the economic emergency is past. Ideally, all public works should meet objective criteria. But as we know too well from the experience of the Republican Congress, a lot of public works spending is just pork—the famous "bridge to nowhere" in Alaska being the best example. It is a certainty that some, perhaps much, of the spending being initiated as stimulus will be just as wasteful. That will be true even if there are no earmarks in the legislation, because when decisions are made in haste without proper vetting, waste is inevitable….
The trick [to boosting the short-run economy] is to make sure that stimulus measures really stimulate, which means that they must affect the economy very quickly, over the next 18 months. Anything that would come online after that must be justified on its merits and not on the looser criteria of being stimulative. One way of ensuring this is the case would be to put in place long-term deficit reduction measures now, which would reassure financial markets that the federal government will not be crowding out private borrowers when the economy turns the corner. (See the testimony of Alice Rivlin and Robert Reischauer, both prominent Democratic economists, before the Senate Budget Committee Jan. 21.)