As expected, Texas Gov. Rick Perry took the brunt of the hits on Wednesday from the other presidential candidates at the latest Republican debate.

Perry hoped to damage the candidacy of former Massachusetts Gov. Mitt Romney by attacking Romney's record on jobs as governor of Massachusetts, but Perry's comments on Social Security were more memorable. Perry's unapologetically tough rhetoric on the New Deal-era program will be used against him for as long as he stays in the presidential campaign.

Romney made an effort to distinguish himself from Perry on Social Security, a program Perry called a "failure."

Perry doubled down on the tough language he used to describe Social Security in his book, calling the program, among other things, a "monstrous lie" to the nation's young people.

"The issue in the book 'Fed Up' Governor, is you say that by any measure, Social Security is a failure," Romney said to Perry. "You can't say that to tens of millions of Americans who live on Social Security and those who have lived on it."

"A candidate should be committed to saving Social Security," Romney added.

Watch:

Perry defended his past comments when he called Social Security a "Ponzi scheme."

"I don't care what anyone says," Perry said when a debate moderator pointed to two other Republicans who disagreed with his use of the phrase. "We know that, the American people know that, but more importantly, those 25-and-30-year-olds know that."

When pressed on his views on climate change, Perry didn't budge from his comment that scientists have not come to a consensus over its existence.

Here's the exchange between him and moderator John Harris, the editor in chief of Politico, the political news website:

HARRIS: Governor Perry -- Governor Perry, Governor Huntsman were not specific about names, but the two of you do have a difference of opinion about climate change. Just recently in New Hampshire, you said that weekly and even daily scientists are coming forward to question the idea that human activity is behind climate change. Which scientists have you found most credible on this subject?

PERRY: Well, I do agree that there is -- the science is -- is not settled on this. The idea that we would put Americans' economy at -- at-- at jeopardy based on scientific theory that's not settled yet, to me, is just -- is nonsense. I mean, it -- I mean -- and I tell somebody, I said, just because you have a group of scientists that have stood up and said here is the fact, Galileo got outvoted for a spell.

But the fact is, to put America's economic future in jeopardy, asking us to cut back in areas that would have monstrous economic impact on this country is not good economics and I will suggest to you is not necessarily good science. Find out what the science truly is before you start putting the American economy in jeopardy.