Nine candidates for the Republican nomination for president take the stage to debate Thursday night in Orlando.

On the day a Quinnipiac poll showed Rick Perry leading the GOP pack in Florida, but Mitt Romney beating President Obama in a general-election matchup, the two Republican front-runners sparred over conservative credentials Thursday night at a Fox News debate in Orlando.

Perry poked Romney over softness or contradictions in the former Massachusetts governor's positions on health-care reform and taxes. Echoing previous encounters, Perry accused Romney of flip-flopping on issues.

But Perry took heavy fire -- and a few boos -- on immigration. Minnesota Congresswoman Michele Bachmann, former Pennsylvania Sen. Rick Santorum, former House Speaker Newt Gingrich and Romney variously hammered the Texas governor for opposing construction of a border fence while awarding in-state tuition to illegal aliens.

"Governor Perry supports national health insurance [spanning] the U.S. and Mexico border," Santorum said in a caustic exchange with Perry. "Even Barack Obama wouldn't propose that,"

Not disputing that point, Perry again found himself on the defensive over his state's law that allows illegal aliens to take advantage of tuition discounts for in-state students.

"I don't think you have a heart [if you oppose it]," he said to a mixture of cheers and catcalls.

Undercutting Perry's claims to economic success -- and further eroding his standing on the immigration issue -- the Center for Immigration Studies reported that only 20 percent of the new jobs in Texas under his administration have gone to native-born Americans in the state.

With Romney widening his lead in the New Hampshire polls, Florida appears to be a must-win for Perry. But the audience of nearly 5,000 Presidency 5 delegates and registered guests did not appear any more enthusiastic toward Perry than to the other eight candidates on the stage at the Orange County Convention Center.

Indeed, as the debate wore on, Perry's attacks on Romney appeared to lose effectiveness, and earlier cheers for him turned to murmurs in the crowd. A post-debate focus group conducted by Fox showed widespread defections from Perry to other candidates, mainly Romney.

While there was broad agreement among the nine candidates on the economic philosophy of free markets and less government regulation, other issues defined their differences.

Two libertarian-leaning hopefuls -- U.S. Rep. Ron Paul and former New Mexico Gov. Gary Johnson -- received raucous cheers for their states' rights views.

In a burst of humor, Johnson said, "My neighbor's two dogs have created more shovel-ready jobs than this current administration."

Businessman Herman Cain evoked cheers for his "9-9-9 plan," which would set a 9 percent personal income tax rate, a 9 percent corporate tax rate and a 9 percent national sales tax.

Cain, a survivor of Stage 4 colon and liver cancer, also scored personal points with the audience when he accused Obamacare of death-dealing delays and bureaucratic "micromanagement."

Bachmann, who won the Iowa straw poll, said she would "repeal the entire federal education law and turn out the lights and lock the doors at the Department of Education."

Gingrich, pledging to unveil a "21st Century Contract With America," gained some respect from Santorum, Perry and Cain, each of whom mentioned him as a hypothetical running mate. Gingrich declined to return the compliment.

Former Utah Gov. Jon Huntsman, continuing to struggle to enunciate a centrist agenda, saying he supports natural gas subsidies as a bridge toward more renewable energy programs.

Contact Kenric Ward at kward@sunshinestatenews.com or (772) 801-5341.