Republican contenders go after Cain on tax plan
The debate was the fifth since Labor Day, and the last scheduled for nearly a month in a race that is fluid in more than one way.
While polls chart a series of rises and falls for various contenders - Romney remaining at or near the top - the schedule is far from set. Florida's decision to move up its primary set off a scramble as Iowa maneuvered to make sure its caucuses are the first real test of the race and New Hampshire works to protect its half-century distinction as host to the first primary.
It was Perry who instigated the confrontation over immigration, saying that Romney had no credentials on the issue because he had once hired an illegal worker, the "height of hypocrisy."
Romney denied the charge, saying he had hired a company to mow his lawn and did not know that it had an illegal immigrant on its payroll. The two men talked over one another, and at one point, Romney placed his hand on Perry's shoulder.
"It's been a tough couple of debates for Rick. And I understand that so you're going to get testy," he said.
As Perry continued to speak, Romney stopped him: "You have a problem with allowing someone to finish speaking, and I suggest that if you want to become president of the United States, you've got to let both people speak," he said.
On a more substantive level, Perry said he opposed repealing the portion of the 14th Amendment to the Constitution that says anyone born in the United States is automatically a citizen.
Bachmann, Santorum and Rep. Ron Paul of Texas all sidestepped the question.
Cain found himself on the defensive on two others issues during the two-hour debate.
He apologized for earlier remarks about building an electric fence on the Mexico border that could kill people trying to cross illegally.
And he said he wouldn't be willing to negotiate with terrorists, even though he had appeared to suggest he might be in an interview earlier in the day.
Former Utah Gov. Jon Huntsman skipped this debate, saying he was boycotting the Nevada caucuses in a dispute over the primary and caucus calendar. He is campaigning exclusively in New Hampshire in hopes of a victory that can move him into the thick of the race.
Not only Republicans, but Obama was also critical of Cain's economic plan during the day. In an interview with ABC News, Obama said it would be a "huge burden" on middle-class and working families.
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