Republican presidential candidate Texas Gov. Rick Perry answers a question as Republican presidential candidate former Massachusetts Gov. Mitt Romney listens during a Republican presidential candidate debate at the Reagan Library Wednesday, Sept. 7, 2011, in Simi Valley, Calif. (AP Photo/Jae C. Hong) (Jae C. Hong/AP)

The surprise is how quickly it happened. As moderator Brian Williams quipped, both candidates came prepared.

In the first few minutes of the NBC News/Politico debate at California’s Reagan Library, the Texas governor and former Massachusetts governor attacked each other’s records on jobs and the economy in detail.

Perry pointed out that Romney, with all his private sector experience, “had one of the lowest job creation rates” in the country as governor — “we created more jobs in the last three months in Texas.” (Here’s a Factchecker on Perry’s jobs record.)

Romney argued that Perry benefited from an external environment in Texas that did not exist in Massachusetts, and that taking credit for the state’s job creation “is like Al Gore saying he invented the Internet.” The zinger got a big laugh.

But Perry had his own historical reference, charging that Michael Dukakis (one of Romney’s Democratic predecessors in Massachusetts and the 1988 Democratic presidential nominee) was a more rapid job creator. Romney retorted that George W. Bush created jobs in Texas faster than Perry.

Later in the debate, the two sparred over Social Security, with Perry reiterating claims he has made that the retirement program is a “Ponzi scheme” and a “monstrous lie” to “our kids” because it can’t remain solvent for future generations.

When pressed by moderator John Harris about GOP political guru Karl Rove — who has a rocky history with Perry and his allies — calling the governor’s remarks about Social Security “toxic, ” Perry responded: “Karl has been over the top for a long time. I’m not responsible for Karl any more.”

Meanwhile, Romney responded that Perry was wrong to suggest that Social Security was failing.

“It’s been working for millions of Americans and I will keep it working for millions of Americans,” Romney said.

Perry started out very calm and confident, despite appearing in his first debate in five years — he refused to debate his last gubernatorial opponent — and his first debate as a presidential contender.

Romney continued his strategy of avoiding fights, responding when attacked but otherwise passing on chances to needle his rivals.

The former governor’s campaign, on the other hand, isn’t pulling punches. Throughout the debate, Romney’s press team sent out detailed memos attacking Perry’s record and his comments.

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