As to the perfect and the good, I don't think the analogy applies here. No one that I have seen is looking for a perfect program. They are saying that neither government dollars nor political will are fungible: politically, the WH can't afford any false starts, and on the financial side, it might have been better (not perfect) to spend $3 billion dollars somewhere else, like on mass transit or high-speed rail.

Thanks for reading and commenting. As to statistics, it will obviously be some time before we have any statistics on the long-term impact of the CARS program. But, Mankiw's thesis is that you have to discount the mileage improvement by factoring in the the multiplier for increased miles driven. 69% sounds great, but I'll wait for some independent research rather than relying on a press release from the third day of the program.

The numbers that we are getting now don't look good for the program's prospects as a sustainable economic stimulant or a long-term way of getting "clunkers" off the road.

As Edmunds.com reported (http://online.wsj.com/article/BT-CO-20090811-710587.html), CARS rebates peaked in the first few days of the program, and industry watchers now have some concerns about a production bubble in auto manufacturing.

Surely 69% fuel economy improvement is hardly going to add carbon.

http://www.reuters.com/article/pressRelease/idUS2…

We should be celebrating getting al these 5 mpg to 17 mpg vehicles off the road.

This one is a great example of letting the perfect be the enemy of the good. Is Cash-for-Clunkers a good idea? Of course! Any idiot can see that it's a good idea!!! But is it perfect? Might it even have some neglible negative side-effects? Maybe so.

So then the nay-sayers would have us do what? Nothing?!? I wonder if FDR had to put up with this kinda crap.