This was a great, great article. Thank you for writing it.

Arnold,
I re-read Krugman's Tax Con essay, and found it chock-full of quantitative information, in addition to the opinions about tax-cutter's motives. In fact, the discussion of motives was essential to Krugman's analysis, since the supply-side stimulus argument was debunked in a very specific, factual fashion, leaving the government-cutting motive as our real policy choice. In other words, IMO Krugman's essay contains both M- and C-arguments. (The consequence of the current tax policy is an Argentina-style debacle, which will lead to massive cuts in government services.)
Don
P.S. The Comptroller General agrees with Krugman.
http://www.latimes.com/news/nationworld/nation/la-na-deficit7oct07,1,1956110.story?coll=la-headlines-nation

What Don said. When you've established that a policy is flat contradictory to the facts (Bush's 1+1=3 arithmetic on Social Security), following up with a motivation argument is just supporting details. You can't just say "X is flat out wrong"; it's useful to examine the process that brought them to that conclusion. It's especially important when those you're disagreeing with are actually commiting the rhetorical equivalent of 1+1=3.

I think you also miss that most of the time Krugman doesn't agree with the premise and assumptions of those he disagrees with, at all; it's not a argument based on trade-offs of "this much inequality for this much in long-run growth", which is how you frame your examples. It's "vouchers will improve school performance" vs. "no they won't."

For example, how is a deficit-financed tax cut supposed to increase long-run growth rates? The usual response is "it'll force spending cuts" - but notice this is a motivation-based argument itself, and then you're off to the races about whether it's democratic or not, public choice, etc., etc.

Is not a "M" argument essentially a subtype of an "ad hominem" argument? I think the "M" vs. "C" description and analysis you have made is a useful way of making an important distinction. Theoretically a U.S. president could lose his mind, develop motives malicious towards a specific group of citizens (whether the rich or the poor or anyone else, however defined), successfully implement his policy (after convincing Congress to go along), yet create results completely contrary to his malicious intent. In short, in the president's insanity, he seeks to harm a group of citizens he's identified as deserving of his ill intent, but he implements a policy that--despite his harmful intent--ends up benefiting that group.

The assumption behind most "M" arguments, one could argue, might simply be that if you grant that the decision maker to whom you attribute malice nonetheless accurately understands cause and effect in his decision making, his malicious motives will lead him to enact policy (cause) which causes harmful effects for those his malice targets. In other words, a "M" argument, whenever it has any power, assumes the validity (at least in the mind of the decision maker) of "C" thinking skills. If a president, i.e., does indeed have such "C" skills, and we attribute to him unworthy motives, we assume that, unchecked, the president will successfully embody the results sought in those unworthy motives. So by pointing out the illegitmacy of the president's motives, we implicitly point to the undesired outcome which will result from his acting on them.

Essentially, we blend two different types of reasoning without distinguishing between them.

Well, suppose you run into something like this, from Larry Lindsey the summer before last:

'Let's take steel first. I am not telling anything here that wasn't public. There were two legitimate economic points.... One argument is that tariffs are never good. I certainly taught that in my economics class. The other argument [represented by Zoellick and Evans] is a little bit more subtle. The world has excess capacity in steel. In any market where that is the case, price is going to be at marginal cost, and marginal cost is going to be below long-run average total cost.... Either you say, "OK, we'll let our firms exit, and we'll let other countries pick up [the business], and we'll just import our steel." Or you say, "Well, that's not a very tenable long-run strategy for any country, because you are effectively letting others pick which industries are going to prevail." Do you unilaterally disarm, or do you use laws that are now on the books?.... There is a sound economic case for doing what we did.'

No you know--I know--Larry knows--that this is unmitigated bulls***, and that none of the three of us believe it. What is the right response? Is it to stick to making only "C" arguments, and to pretend to take Larry seriously? Or is the right response to make the "C" arguments, and also make the "M" argument that Larry is being a sock puppet for Karl Rove because he wants to keep his White House mess privileges?

It's a hard question. But there are clearly times--like this example--when sticking to the "C" arguments is a way of misleading your readers. All the substantive economic policy guys in the Bush administration were horrified by the steel tariff. And to pretend that they weren't horrified--that they believed what they said in their sock puppet role, and that there was a serious debate between two serious schools of analysis--is so close to lying to your readers that I cannot really see a difference.

I am compelled to agree with Brad DeLong. The conservative economists defending the ludicrous attempts to protect our steel industry from foreign competition should be ashamed of themselves. They are truly practicing the art of “if you wish to get along, you must go along.” However, doesn’t this also place Professor DeLong in an awkward situation? The Republicans are at least the lesser of evils. Does he really believe that the likely Democrat presidential candidate will advocate better economic policies? Sigh, if Brad DeLong indeed does believe such a fantasy---I have some swamp land in Florida to sell him!

I adamantly predict that Brad DeLong will suffer a long dark night of the soul in November of 2004. He will probably be unable to vote for the Democrat candidate opposing President Bush.

My response to Brad is that he should stick to the type C argument. I'll spell that out in a full post.

Seeing as how Brad DeLong was able to work for a Democratic president in the reasonably near past, I do not think that he will have that difficult of a time pulling the lever for a Democrat. Especially since the guide of recent history has shown that it was a Democratic president who was able to push for and implement more free trade, wider globalization, and structurally balanced budgets. These are things that most economists really like, and the Democrat delivered while Bush has not. The current Democrats are also professing that they believe in structurally balanced budgets and they are no worse than Bush on trade issues and probably better than Bush on current accounts and long term solvency issues. So I do not think it requires much imagination for fiscally and economically responsible people to be voting against Bush in 2004 and for a Democrat.

Fester

“Seeing as how Brad DeLong was able to work for a Democratic president in the reasonably near past, I do not think that he will have that difficult of a time pulling the lever for a Democrat.”

“Near past?” The Clinton administration took power some eleven years ago. That is an eternity in our future shock political milieu. I am utterly convinced that a free trade Democrat doesn't have a chance of winning the nomination in 2004. *Bill Clinton is far too conservative for today’s leftist Democrats. These ideologues have little interest in forming a working partnership with the business and investment communities.

The current nominating process will make it virtually impossible for the eventual winner (likely Howard Dean) to shift back to the political middle during the general election. It also stuns me to no end that both Brad DeLong and other Neo-liberals even suggest that the Democrats would do a better job of balancing the budget. The left wing Democrats who currently dominate the party’s national agenda advocate spending programs that would make the Bush White House seem like Calvinist penny pinchers!

* Yup, I mean exactly that. Bill Clinton is too far to the right to satisfy the crazy people who will select the next Democrat presidential candidate.