GOP debate in Arizona (10 images)

Republican Presidential candidates Ron Paul, Rick Santorum, Mitt Romney, and Newt Gingrich (L-R) stand on stage as the National Anthem is played before the start of the Republican Presidential Debate at the Mesa Arts Center in Mesa, Arizona, February 22, 2012. UPI /Art Foxall

Ron Paul, Rick Santorum, Mitt Romney, and Newt Gingrich (L-R) stand on stage before the start of the Republican Presidential Debate at the Mesa Arts Center in Mesa, Arizona, February 22, 2012. UPI /Art Foxall

Ron Paul, Rick Santorum, Mitt Romney, and Newt Gingrich (L-R) shake hands before the Republican Presidential Debate at the Mesa Arts Center in Mesa, Arizona, February 22, 2012. UPI /Art Foxall

Mitt Romney sings the National Anthem before the Republican Presidential Debate at the Mesa Arts Center in Mesa, Arizona, February 22, 2012. UPI /Art Foxall