Former Massachusetts Gov. Mitt Romney (left) and Texas Gov. Rick Perry got into a heated exchange about immigration during Tuesday's GOP presidential debate in Las Vegas.

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Herman Cain (left) watched as former Massachusetts Gov. Mitt Romney (center) and Texas Gov. Rick Perry spoke during what became a heated Republican presidential debate Tuesday night in Las Vegas.

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An unmanned ROV (remotely operated vehicle) is launched 900 feet underwater to study the wreckage of the SS Montebello.

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New Jersey Gov. Chris Christie kept his fans guessing about whether he'll make a run for president during an appearance Tuesday night at the Ronald Reagan Presidential Library and Museum in Simi Valley, Calif. Kevork Djansezian/Getty Images hide caption

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Republican presidential candidate Rep. Michele Bachmann arrives for a rally in Costa Mesa, Calif., on Friday. Chris Carlson/AP hide caption

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California Rep. Xavier Becerra was one of six Democrats chosen to join six Republicans on a panel tasked with finding a way to cut about $1 trillion from the federal deficit. Kris Connor/Getty Images hide caption

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Metropolitan State Hospital employees and supporters gather outside the gates of the hospital in Norwalk, Calif., earlier this month to protest repeated assaults at the hands of mental patients and what they call dangerous working conditions. Nick Ut/AP hide caption

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Members of the Ford family pose on the White House grounds in this undated photo. From left, standing: Son Steve; daughter Susan; son Jack; son Michael's wife, Gayle; and Michael. Seated in front: President Gerald and first lady Betty Ford. AP hide caption

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