You heard of this thing, 4 percent growth? Yeah, this is going to blow that right out of the water. Photo: Scott Olson/Getty Images; Twentieth Century Fox

Jeb Bush has made the ludicrous promise that, if elected, his still to-be-determined economic program will launch the United States into 4 percent economic growth. Reuters reported out the genesis of this promise a few months ago. “There were no fancy economic models or forecasts when former Florida Governor Jeb Bush first tossed out the idea that 4 percent annual growth should be the overarching goal for the U.S. economy,” it revealed. Just a bunch of guys on the phone pullin’ numbers out of thin air:

That ambitious goal was first raised as Bush and other advisers to the George W. Bush Institute discussed a distinctive economic program the organization could promote, recalled James Glassman, then the institute’s executive director. “Even if we don’t make 4 percent it would be nice to grow at 3 or 3.5,” said Glassman, now a visiting fellow at the American Enterprise Institute. In that conference call, “we were looking for a niche and Jeb in that very laconic way said, ‘four percent growth.’ It was obvious to everybody that this was a very good idea.”

(George W. Bush’s policies didn’t produce anything close to 4 percent annual growth, but the Bush Institute has made 4 percent growth its major theme, in keeping with the general Republican practice of acting like the Bush administration never happened.)

But there’s a weakness in basing your economic message on pulling a crazy number out of thin air: Another candidate can always pull an even crazier number out of thin air. And now Mike Huckabee has done it. The obvious choice would be to one-up Bush by promising 5 percent growth. But Huckabee, thinking two steps in advance, probably realized that if he went with 5 percent, another candidate could still leapfrog him. So he went with 6 percent growth:

Huckabee, the winner of the 2008 Iowa caucuses, who is running as an economic populist, said 6 percent growth or more — notably upping the ante over Jeb Bush’s promise of 4 percent growth — would be possible through what he calls the Fair Tax, a type of national sales tax. Economists have expressed skepticism at Mr. Bush’s promise of 4 percent growth, so Mr. Huckabee’s 6 percent plan may cause even more raised eyebrows.

The beauty of this is that Bush can hardly call Huckabee’s promise unrealistic or made-up, without having to concede his own promise is also unrealistic and made-up, just less so. Bush has no grounds to argue against Huckabee here. Think about it. You walk into a caucus, you see 4 percent growth sittin’ there, there’s 6 percent growth right beside it. Which one are you gonna pick, man?