Texas Gov. Rick Perry, from left, former Sen. Rick Santorum of Pennsylvania, former Massachusetts Gov. Mitt Romney, former House Speaker Newt Gingrich and Rep. Ron Paul of Texas prepare to take the stage at the Republican debate in Myrtle Beach, S.C. (Mark Wilson / Getty Images)
Republican presidential candidates take part in the South Carolina debate.
Arriving onstage for the Republican debate in Myrtle Beach, S.C., are, from left, Rick Perry, Rick Santorum, Mitt Romney, Newt Gingrich and Ron Paul. (Emmanuel Dunand / AFP/Getty Images)
Former Pennsylvania Sen. Rick Santorum, left, and former Massachusetts Gov. Mitt Romney share a sharp exchange during the Republican debate. (Charles Dharapak / AFP/Getty Images)
Rep. Ron Paul, right, of Texas drives home a point as former House Speaker Newt Gingrich reacts during the debate. (Charles Dharapak /AFP/Getty Images)
Texas Gov. Rick Perry, left, speaks as former Sen. Rick Santorum of Pennsylvania listens during the Republican debate in Myrtle Beach. (Charles Dharapak / AFP/Getty Images)
