I think Paul Krugman’s critiques of Barack Obama (starting early in the primary season and continuing today) represent one of the most interesting debates in American politics. Here’s a simplified version:

Krugman: The problem with America is conservatism, which is wrong and bad. A failed conservative president represented a golden opportunity to make the anti-conservative case in a way that would permanently change American politics. This argument had to be made forcefully, without rhetorical compromise or nuance. The Republicans had to be sent packing, with Bush hung around their necks.

Obama: The problem with America is a set of poor relationships–relationships among citizens, between the public and the government, and between America and other countries–that make good governance impossible. The Bush disaster happened because of public alienation, low expectations, polarization, and a neglect of shared values. There are many reasons for public distrust of government. Poor performance is one. Another is that half of our representatives in Washington keep saying that the other half are crooked and idiotic, and then the other half says the same back. To rebuild essential relationships will require dialog and civility.

Now Krugman says that the stimulus plan is too small, and the cuts engineered by “centrist” Senators have made it worse. “But how did this happen? I blame President Obama’s belief that he can transcend the partisan divide–a belief that warped his economic strategy.”

The stakes are as high as can be, and if Krugman is correct, Obama’s whole “theory of change” is badly flawed.

We don’t really know how big a stimulus is big enough, but when a Nobel prize-winner says that $800 billion is too small, who am I to argue? What I would question is Krugman’s political explanation for how that number arose. Obama annoyed Krugman by meeting with Republicans and conservatives, acting respectfully toward them, and appearing to welcome negotiation. I think that behavior was completely unrelated to the outcome of the bargaining in Congress. The Administration could have proposed a $1.2 trillion stimulus, followed by much respectful listening and negotiation. The result would have been a $1 trillion package–more acceptable to Krugman the economist (but perhaps just as annoying to Krugman the political strategist). Instead, the Administration started lower and ended at around $800 billion. I doubt very much that they chose their original number because they thought it would encourage dialog and civility. Economic and administrative considerations must have determined that initial number. Perhaps it was too low, but that had nothing to do with Obama’s style of interaction after he put a bid on the table.

As I’ve written several times before, it is not just the editorial board of the Washington Post that likes bipartisanship. The public likes it, and that shows in Obama’s stratospheric popularity right now. People think that he’s trying to deliberate. Once he tries to talk, he’s free to criticize the opposition. That’s not merely a clever strategy,; it’s also good manners.

Obviously, being popular is not an end in itself. But the public will oppose government spending unless they respect the people in charge of the government; and comity is the path to respectability.

Here’s what I’m left unsure of. Presuming that $800 billion is too little money, which of the following is true?

1. For psychological reasons–to break the cycle of recession–it’s necessary to spend enough money in one initial bang. $800 billion isn’t enough, so the recession will worsen. The government will spend more, but too late. Obama will govern for four years of deep pain and will be unable to achieve any substantive domestic reforms.

— or —

2. The government cannot do a good job passing and implementing legislation that costs more than $800 billion. (Even that amount is a major stretch.) But they can spend more later, including another big dose for health care reform. To be sure, the legislative rules regarding how deficits are “scored” will change after the stimulus passes; but rules can be changed again. As long as the total amount spent in FY 09 and FY 10 is sufficient, it’s better to do it more deliberately and in a spirit of maximum comity that the American people admire.

I obviously hope that #2 is correct, but #1 could be better economics.