Mitt Romney

Republicans Debate_Lea(1).jpg

Texas Gov. Rick Perry (left) and former Massachusetts Gov. Mitt Romney take part in the Republican presidential debate on Saturday, Dec. 10, 2011, in Des Moines, Iowa. (AP Photo/Charlie Neibergall)

Republican presidential candidates former Massachusetts Gov. Mitt Romney, left, and former Speaker of the House Newt Gingrich, right, take part in the Republican debate, Saturday, Dec. 10, 2011, in Des Moines, Iowa. (AP Photo/Charlie Neibergall)

DEBATE.jpg

Republican presidential candidates, from left, former Pennsylvania Sen. Rick Santorum, Texas Gov. Rick Perry, former Massachusetts Gov. Mitt Romney, former Speaker of the House Newt Gingrich, Rep. Ron Paul, R-Texas, and Rep. Michele Bachmann, R-Minn, take their place for a Republican debate, Saturday, Dec. 10, 2011, in Des Moines, Iowa. (AP Photo/Eric Gay)

GOP.jpg

** FILE ** In this Nov. 9, 2011, file photo Republican presidential candidates former House Speaker Newt Gingrich and former Massachusetts Gov. Mitt Romney laugh before a Republican presidential debate at Oakland University in Auburn Hills, Miss. (AP Photo/Paul Sancya, File)

20111208-210159-pic-1642054.jpg

Former Massachusetts Gov. Mitt Romney, Newt Gingrich's presidential-primary rival , waves to supporters as he gives a television interview after a campaign event in Paradise Valley, Ariz., on Tuesday. (Associated Press)

romney.jpg

Republican presidential candidate, former Massachusetts Gov. Mitt Romney, speaks to supporters and volunteers during a rally Saturday, Dec. 3, 2011, in Manchester, N.H. (AP Photo/Jim Cole)

20111201-205827-pic-729519468.jpg

Republican presidential candidate Mitt Romney stumps in Florida. He has dramatically boosted his campaigning in Iowa with just a month to go before caucuses there. (Associated Press)

20111129-223749-pic-250582128.jpg

Republican presidential hopeful Mitt Romney signs autographs after speaking at a campaign stop Tuesday in Medley, Fla. While his rivals focus on Iowa's caucuses or the early primaries in New Hampshire and South Carolina, the former Massachusetts governor is spending time this week in Florida. (Associated Press)

20111127-195636-pic-210167579.jpg

New Jersey Gov. Chris Christie, a Republican, campaigns for GOP presidential hopeful Mitt Romney in Manchester, N.H., on Nov. 9. Surrogates such as Mr. Christie have been scarce thus far this election cycle, partly because voters want to meet the candidates themselves. (Associated Press)

20111124-200601-pic-318673700.jpg

To become the GOP standard-bearer, Mr. Santorum must leapfrog past rivals (from left) Mitt Romney, Herman Cain and Newt Gingrich. (Associated Press)

20111123-193817-pic-235676964.jpg

Republican presidential candidate Mitt Romney, with Sen. John Thune of South Dakota, speaks Wednesday to workers at Nationwide Insurance Co. in Des Moines, Iowa. Mr. Romney is using a tough stance against illegal immigration to separate himself from his rivals for the nomination. (Associated Press)

APTOPIX Republicans D_Star.jpg

Republican presidential candidate Rep. Ron Paul of Texas speaks as Texas Gov. Rick Perry and former Massachusetts Gov. Mitt Romney listen at a Republican presidential debate in Washington on Nov. 22, 2011. (Associated Press)

Republicans Debate_Reps.jpg

Republican presidential candidates from left, former Massachusetts Gov. Mitt Romney shakes hands with businessman Herman Cain, as former House Speaker Newt Gingrich stands on stage before a Republican presidential debate in Washington, Tuesday, Nov. 22, 2011. (AP Photo/Evan Vucci)

TV Fair Debates_Live.jpg

**FILE** Republican presidential candidates (from left) former Utah Gov. Jon Huntsman, Rep. Michele Bachmann of Minnesota, Rep. Ron Paul of Texas, businessman Herman Cain, Former Massachusetts Gov. Mitt Romney, former House Speaker Newt Gingrich, Texas Gov. Rick Perry, and former Pennsylvania Sen. Rick Santorum prepare Nov. 12, 2011, before the CBS News/National Journal foreign policy debate in Spartanburg, S.C. (Associated Press)

20111120-204302-pic-997795601.jpg

Former Massachusetts Gov. Mitt Romney, a Republican presidential candidate, speaks to supporters outside City Hall in Nashua, N.H., on Sunday. Sen. Kelly Ayotte (left) of New Hampshire listens. Mrs. Ayotte endorsed Mr. Romney. (Associated Press)

20111120-203351-pic-711259278.jpg

Republican presidential candidate Mitt Romney, a former Massachusetts governor, has said the United Nations too often becomes a forum for tyrants when it should promote democracy and human rights. (Associated Press)

20111113-181354-pic-93558784.jpg

Republican presidential hopeful Mitt Romney greets supporters in Troy, Mich., on Thursday. The night before, in a GOP candidates debate, the former Massachusetts governor sought to defuse criticism of his changing his views on the issues. (Associated Press)

Republicans Debate_Live(1).jpg

Republican presidential candidates Newt Gingrich (right) and former Massachusetts Gov. Mitt Romney participate in the CBS News/National Journal foreign policy debate at the Benjamin Johnson Arena in Spartanburg, S.C., on Nov. 12, 2011. (Associated Press)

debate.jpg

Republican presidential candidates Newt Gingrich (left) and former Massachusetts Gov. Mitt Romney participate in the CBS News/National Journal foreign policy debate at the Benjamin Johnson Arena in Spartanburg, S.C., on Nov. 12, 2011. (Associated Press)

20111106-193113-pic-173302045.jpg

Former Massachusetts Gov. Mitt Romney, a Republican presidential candidate, laughs with servers at Mary Ann's Diner during a campaign stop in Derry, N.H., in June. The eatery, decorated in '50s and '60s decor, is a must-visit campaign stop for presidential candidates campaigning in New Hampshire. (Associated Press)