And what will be the opportunity cost of the current stimulus plan? If it works the way it should, nothing. The resources to be used would have been idle anyway. More investment is likely to be crowded in than crowded out—construction companies buying new cranes to work on those highways and schools. It's not like interest rates are going to go up much. The deficit might even be smaller than it would have been with a full-blown depression. If we pay for the extra spending by printing money that will be discreetly drained away later, or by selling government bonds with rock-bottom interest rates, there won't even be much effect on the nominal national debt. So I wish everybody would just quit worrying so much. If there's any case against the stimulus, it has to be about all the non-stimulating things that are in there, like AMT relief. But that's just political horse-trading.
The important thing is that fiscal policy and monetary policy are working together for once. When they don't, we have disasters. In this case, the fiscal stimulus to aggregate demand has to run parallel to the repair of the financial markets and aggressive monetary ease. One without the other won't do much good.