Rick Perry and Mitt Romney Wrangle Over Immigration

As expected, immigration was an incendiary subject at the CNN Debate Tuesday night in Las Vegas.

Rick Perry called Mitt Romney a "hypocrite" for allowing illlegal workers at his residence, and Romney countered by accusing Perry of turning Texas into "a magnet" with in-state college tuition.

Perry favors "virtual" and "strategic" fencing, and "boots on the ground" to patrol the border. But he drew boos from the audience when he revisited Romney's employment issue.

Herman Cain and Michele Bachmann took particularly hard lines on the border.

"Empower the states to do what the federal government has not been doing," said Cain, who reiterated his support for a border fence.

Bachmann also supports construction of a fence, and added that the illegal immigration problem reaches all the way to the White House. "Obama is the problem, with an uncle and aunt staying in this country illegally."

She cited a report that estimates illegal immigration costs the country $113 billion a year.