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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In September 2008, then-Sen. Barack Obama disembarks from his campaign plane in Reno. Mayor Bob Cashell says presidential candidates should spend a little more face time in his town. Emmanuel Dunand/AFP/Getty Images hide caption

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Many bloggers and social media activists at the Netroots Nation Convention say they have become disenchanted with President Obama's administration. Jacquelyn Martin/AP hide caption

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Huckabee signs a copy of his new book, A Simple Government: Twelve Things We Really Need from Washington (and a Trillion that We Don't!), at the National Press Club, February 2011 in Washington. Chip Somodevilla/Getty Images hide caption

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Republican state Sen. Sam Blakeslee, shown at a committee hearing earlier this year, says the Atascadero hospital has "an inherently dangerous population." He's proposed new laws designed to make the hospital safer, including a bill that would make it easier to medicate patients against their will. Rich Pedroncelli/AP hide caption

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At a rally at Napa State Hospital in January, workers demand better safety measures for staff and patients. One worker carries a sign with a photo of Donna Gross, a hospital worker killed last year, allegedly by a patient. J.L. Sousa/ hide caption

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