Jonath makes the mistake of taking the McCain "economists" letter as an analytical statement, rather than as an expression of attitude written by spinmasters, and demands intellectual consistency:

Economists for Obama: McCain's Economist Supporters vs. Facts: Over at MarginalRevolution, Tyler Cowen has posted the text of an email... prominent, right-leaning economists (who) have endorsed John McCain's stated economic proposals... the usuals (e.g., Becker, Hassett, McCain chief economic adviser Doug Holtz-Eakin, Taylor, Harvey Rosen, Meltzer, etc.)... (NS) prominent economists who have earned their academic reputations.... I've previously discussed the enormous increase in deficits that would be caused by McCain's tax proposals, as scored by Len Burman and Greg Leiserson of the Tax Policy Center. So let me focus on the second paragraph (of the letter), which is uniformly contradicted by both facts and experience:

"His plan would control government spending by vetoing every bill with earmarks." Well, this one has already been repudiated by... John McCain's chief economic adviser, Doug Holtz-Eakin. I've already posted on this issue:

McCain has already had to change his "definition" of those nasty earmarks he'll eliminate (somehow, without a line-item veto). According to this story by the Politico's Ben Smith, Holtz-Eakin initially claimed that there were $100 billion in earmarks in the current budget, the idea presumably being that eliminating all of these earmarks would give McCain $100 billion to work with in paying for his tax cuts. After a former senior Democratic staffer, Scott Lilly, pointed out that many of these earmarks included stuff McCain supports, like money for Israel, Egypt and U.S. military construction, Holtz-Eakin stated that in fact the real amount of money associated with earmarks McCain would not fund (again, magically preventing them without a line-item veto) was only $16-18 billion.

"(I)mplementing a constitutionally valid line-item veto..." Clearly, this one is there to allow them to respond to criticisms, like the parenthetical reference in my earlier post, based on the fact that under current law, the President has no capacity to pick and choose which items to fund. President McCain will have to sign or veto actual statutes, not their components.... I am not a constitutional lawyer, but given my understanding of the Court's language in Justice Stevens's opinion for the Court, I find it very difficult to imagine that McCain and his lawyers (much less his economists) will be capable of "implementing a constitutionally valid line-item veto".

"(P)ausing non-military discretionary government spending programs for one year to stop their explosive growth..." Gee, I hardly know where to begin on this one. First off, a one-year pause would do nothing to stop "explosive growth". It would reduce the level of spending, to be sure, but then that "explosive growth" would go right on happening. This is a mathematical principle of which each of the economist-letter's signatories no doubt is aware.

That said, this post over at CBPP is worth a look (Update: I see that Mark Thoma posted much of the CBPP post, which I should have noted was written by Richard Kogan, back in March). It shows the following:

Domestic discretionary spending fell from 18.4% of all non-interest federal spending in 2001 to (an estimated) 14.7% in 2008. By comparison, defense and security spending (in which the CBPP includes DHS and Veterans' spending) rose from 21.7% to 29.2%.

The real, i.e., inflation-adjusted, growth rate of domestic discretionary spending over this period was 1.3%. That's hardly an "explosive growth" path; by comparison, defense/security increased 9.1%, while SS/Medicare/Medicaid increased 3.8%.

As a share of GDP, domestic discretionary spending actually fell, from 3.1% to 2.8%. That means that this category of spending has been becoming less, not more, burdensome. Defense/security rose from 3.6% to 5.6% of GDP over this period, while SS/M/M rose from 7.7% to 8.4%.

I am frankly baffled as to what my colleagues on the right are talking about when they discuss "explosive growth" in "nonmilitary discretionary government spending". The real money on the spending side is in the military and entitlement categories....

(I)t is difficult for me to believe that people who promote John McCain's economic policies on the basis of the second paragraph of the letter above can simultaneously be aware of the facts and providing honest assessments. Perhaps I am wrong. I hope so.

I think that the disconnection of the letter from fiscal and economic reality is, from the point of view of the signatories, a feature and not a bug--because the McCain platform is so far out in the Gamma Quadrant, nobody will think that this is what the economists actually believe, and they will not have to spend any time defending it.