It’s true that we’re making progress on deleveraging. Household debt is down to 118 percent of income, and a strong recovery would bring that number down further. But we’re still at least several years from the point at which households will be in good enough shape that the economy no longer needs government support.

But wouldn’t it be expensive to have the government support the economy for years to come? Yes, it would  which is why the stimulus should be done well, getting as much bang for the buck as possible.

Which brings me back to the Obama-McConnell deal. I’m often asked how I can oppose that deal given my consistent position in favor of more stimulus. The answer is that yes, I believe that stimulus can have major benefits in our current situation  but these benefits have to be weighed against the costs. And the tax-cut deal is likely to deliver relatively small benefits in return for very large costs.

The point is that while the deal will cost a lot  adding more to federal debt than the original Obama stimulus  it’s likely to get very little bang for the buck. Tax cuts for the wealthy will barely be spent at all; even middle-class tax cuts won’t add much to spending. And the business tax break will, I believe, do hardly anything to spur investment given the excess capacity businesses already have.

The actual stimulus in the plan comes from the other measures, mainly unemployment benefits and the payroll tax break. And these measures (a) won’t make more than a modest dent in unemployment and (b) will fade out quickly, with the good stuff going away at the end of 2011.

The question, then, is whether a year of modestly better performance is worth $850 billion in additional debt, plus a significantly raised probability that those tax cuts for the rich will become permanent. And I say no.

The Obama team obviously disagrees. As I understand it, the administration believes that all it needs is a little more time and money, that any day now the economic engine will catch and we’ll be on the road back to prosperity. I hope it’s right, but I don’t think it is.

What I expect, instead, is that we’ll be having this same conversation all over again in 2012, with unemployment still high and the economy suffering as the good parts of the current deal go away. The White House may think it has struck a good bargain, but I believe it’s in for a rude shock.