I'm in Tampa, FL for the CNN-Tea Party Express Republican Presidential Debate. The debate begins at 8pm on CNN. I'll be on WSB Radio from 5pm to 7pm doing a "pre-game" show and then, starting at 7pm, I'll be on CNN the rest of the night.When the debate starts, Michele Bachmann intends to join Mitt Romney in defending social security against Rick Perry and his evil, awful "ponzi scheme" comment.To be clear, none of the Republican Presidential candidates, except Ron Paul, wants to abolish social security. Not even Rick Perry who, though he wrote it was an affront to our constitutional system, made clear in both his book and on stage in California that he was not going to refight 70 years of American legislative progress, but would instead work to fix a broken system.But Romney and Bachmann intend to keep going after Rick Perry for his "ponzi scheme" comment.They might want to reconsider. Alex Tabarrok notes at Marginal Revolution that Nobel Prize winning economist Milton Friedman called social security "the biggest ponzi scheme on earth. That was back in 1999.In 1967, Nobel Prize winning economist Paul Samuelson also considered social security a ponzi scheme.Oh, and they aren't the only one's to use the word "ponzi" to describe social security. So did Nobel Prize winning economist Paul Krugman.That doesn't even include Mitt Romney who called the social security system a "criminal enterprise."When you have economists on the left and the right calling social security what it is, you might want to rethink your line of attack.