Indiana Governor Mitch Daniels defended his description of Social Security as a "Ponzi scheme" Tuesday, wading into a debate about the popular entitlement program that has enveloped the Republican primary. Daniels describes the program as such in his yet-to-be-released book, Keeping the Republic, echoing a critique that Texas Gov. Rick Perry made in his own book last year.

Leading Perry challenger and former Massachusetts Gov. Mitt Romney has seized on the "Ponzi scheme" comments , arguing that Perry needlessly "scared seniors" by describing the program in that way. 

But Daniels sought to downplay the significance of the descriptor Tuesday morning on "Fox & Friends." Asked if he stood by his book in light of the recent controversy, Daniels said that he felt the language was appropriate.

"Yeah, as far as it goes, absolutely," Daniels said. "After all this flap recently some people did some quick Googling, and the problem with what Rick Perry says is that it's trite, it's been said so often."

The Indiana governor critiqued the system as inherently flawed and misleading to seniors.

"It's a pay-as-you-go system, you're not putting away — people have been misled over the years to believe they're putting something away for themselves, we know it's not the way it works," Daniels said.

Some establishment Republicans have joined Romney in criticizing the comments. Former Bush adviser Karl Rove called the language "toxic" and Perry's explanation of his position "inadequate." But those in the Perry camp hope that Daniels  a relatively mainstream Republican who many in the party hoped would run for president  provides cover on the issue. 

Of course, Daniels has the luxury of not having another election to worry about; the governor has announced his plans to retire in 2012. But, while having ruled out a run for the presidency, the governor was unwilling to say that he wouldn't consider joining a ticket as a vice presidential candidate.

"You can't say you wouldn't answer if someone called," Daniels said. "It seems so improbable to me and certainly nothing I anticipate and something I hope doesn't happen."