Buoyed by his surging poll numbers, 2012 Republican presidential candidate Rick Perry renewed his call to restructure Social Security by likening the program to a Ponzi scheme.

Speaking to a crowd in Iowa, Perry revived the description he had used in his 2010 book Fed Up! in arguing that Social Security's long-term health would require changes like raising the eligibility age or barring some wealthy Americans from the program. He said that such changes would not affect the generation poised to begin receiving Social Security benefits, people like me.

It is a Ponzi scheme for these young people. The idea that they're working and paying into Social Security today, that the current program is going to be there for them, is a lie, Perry said. It is a monstrous lie on this generation, and we can't do that to them.

The fate of federally funded entitlement programs will likely play a central role in the economic debate sure to dominate this presidential contest. Democrats united in attacking a plan, advanced by Rep. Paul Ryan (R-WI) that would have privatized much of Medicare. But Republicans have continued to push for reforms to Medicare and Social Security, pointing to what they call unsustainable long-term costs as the country grapples with a yawning deficit.

Perry offered a wide-ranging indictment of President Barack Obama's policies, both foreign and domestic. On the economy, he noted that Obama inherited a bad economy, but he sure made it worse, and called for lower taxes and a simplified tax code. He compared Obama's stance on Israel to throwing Israel under the bus.

A reporter pressed Perry on assertions he had made in his book, including charging that Social Security was created  at the expense of respect for the Constitution and limited government. Perry said he was not suggesting that Social Security, or similar programs like Medicare, were unconstitutional.

I never said it was unconstitutional, Perry said. I look at Medicare just like I look at Social Security. They're programs that aren't working and we ought to have a national conversation about it. You know, those that have said I've said they're unconstitutional - I'm going to have them read the book. That's not what I said.