I see that in Ruth Marcus’s defense for the substantive success of the ARRA, nowhere does she present actual evidence of its efficacy. She does assert that fiscal stimulus is “a classic, and sensible, Keynesian response to recession”, something with which I agree.
The problem is that to be effective fiscal stimulus must be of an appropriate size, timed properly, and structured correctly. None of those was the case.
I think that several things were necessary for an effective stimulus. All of it should have been spent as quickly as possible rather than dribbling it out over several years. If it had been as effective as it should have been, political support for it would have grown rather than weakened as it manifestly did. The only way to spend so large a stimulus quickly is through the tax system (remember the president’s rueful remark that he learned there were no shovel-ready projects?). My preference would have been a payroll tax holiday, a complete suspension of both sides of the payroll tax.