Republican presidential hopeful Tim Pawlenty raised a few eyebrows last week, unveiling a breathtaking tax-cut plan that, by some estimates, comes with a $11.6 trillion price tag. The former Minnesota governor insists his proposal, far more radical than anything even proposed by the Bush administration or House Republicans, would lead to 5% GDP growth — a boast so divorced from reality that no one could possibly take it seriously.

Adding insult to injury, Pawlenty said last week those who question his truly preposterous projections “don’t believe in the American people enough.”

Yesterday on Fox News, Chris Wallace asked the former governor, “Doesn’t your plan blow a hole in the national deficit?” Pawlenty replied, “It does not,” adding that “there may be a small impact negatively on the deficit” at first, but over the decade, “this plan more than balances.” Why? Because Pawlenty simply assumes that his tax cuts will lead to 5% growth for a decade — an assumption that’s demonstrably ridiculous.

Wallace, to his credit, noted we’ve never had “10 consecutive years of 5 percent growth.” Pawlenty replied, “Well, this is an aspiration.”

“I don’t buy into the declinist view and attitude of President Obama that we’re going to settle for anemic growth or average growth or that America’s going to be laggard. We’re going to lead the world economically and in all other respects.

“We have achieved 5 percent growth twice in the recent history of this country, once under Reagan, once under Clinton…. So, this idea that we can’t do it in America — hogwash. I believe in the American people. I believe if you unleash the private economy in this country, we can do this.

“Now, we also made it such that if the numbers don’t hit 5 percent and they are a little lower than that, the plan still works.

“So, I don’t buy this defeatist/declinist Obama attitude that America should just accept its place as anemic laggard.”

Speaking of “hogwash,” none of this makes any sense. His memories of the Reagan and Clinton eras are wrong; his insistence that he “believes in the American people” is nice but irrelevant; and to believe in arithmetic is not a “defeatist/declinist” attitude.

When Wallace noted that plenty of conservative economists reject Pawlenty’s numbers, that the Reagan and Clinton numbers he’s so fond of came after tax increases, and that Pawlenty’s plan can’t pay for itself if it falls short of 5% growth, the former governor simply asserted that his numbers add up.

Paul Krugman noted last week that Pawlenty “has turned out to be a much bigger fool than I or, I think, anyone imagined.” Apparently, the former governor is eager to prove Krugman right.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.