SIMI VALLEY, Calif. — Eager to tangle, Republican presidential rivals Rick Perry and Mitt Romney each laid claim to a better job-creating record as governor Wednesday night in a lively campaign debate that marked a new turn in the race to pick a 2012 challenger to President Barack Obama.

“Michael Dukakis created jobs three times faster than you did, Mitt,” Perry jabbed, referring to Romney’s predecessor as Democratic governor in Massachusetts.

“As a matter of fact, George Bush and his predecessors created jobs at a faster rate than you did,” Romney shot back at Perry.

The debate was the first of three in as many weeks, at a time the polls show Obama’s popularity sinking.

Perry and Romney stood next to each other on the debate stage at the Ronald Reagan Presidential Library, a symbolic setting that invoked the memory of the conservative Republican who swept to two terms as president.

Former Utah Gov. Jon Huntsman sided with Perry when he turned to Romney and said, “47th just isn’t going to cut it, my friend,” a reference to the rank Massachusetts had among the 50 states in creating jobs during Romney’s term.

Businessman Herman Cain, Minnesota Rep. Michele Bachmann, Texas Rep. Ron Paul, former House Speaker Newt Gingrich and former Sen. Rick Santorum of Pennsylvania shared the stage for the debate hosted by MSNBC and Politico.

Bachmann said she would provide the “strong, bold leader in the presidency who will lead that effort. None of us should ever think that the repeal bill will just come to our desk,” she said in a pledge that drew applause from the audience.

Gingrich resisted an effort to draw him into conflict with other Republicans on stage. “I’m frankly not interested in your efforts to get Republicans fighting each other,” he said, sparking an even louder round of applause. He said all Republicans should “defeat efforts by the news media” to spark an internal struggle when the real objective is to defeat Obama in 2012.

But moments later, Cain said that after trying to defeat Democratic efforts to create national health care, “I’m running against Romneycare,” the legislation that passed requiring residents of Massachusetts to purchase coverage.