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Democratic presidential candidate Sen. Bernie Sanders, I-Vt., smiles as he is announced to speak at a veterans forum at the Best W Bernie Sanders speaks during a Democratic presidential primary debate Saturday, Dec. 19, 2015, at Saint Anselm College in Manchest Democratic presidential candidate Hillary Rodham Clinton speaks to the Democratic National Committee 22nd Annual Women's Leadershi FILE - In this Monday, Dec. 21, 2015, file photo, Republican presidential candidate Sen. Marco Rubio, R-Fla., points to a potentia Republican presidential candidate Dr. Ben Carson gestures while speaking during a town hall at Abundant Life Ministries in Jeffers Republican presidential candidate Ben Carson speaks during the first Republican presidential debate at the Quicken Loans Arena Thu FILE - In this April 29, 2015 file photo Democratic presidential candidate, Hillary Rodham Clinton is seen in New York. When Hilla Republican presidential candidate, Sen. Marco Rubio, R-Fla. campaigns, Friday, Jan. 15, 2016, at Morse's Sporting Goods in Hillsbo FILE - In this Aug. 19, 2015 file photo, Republican presidential candidate Donald Trump speaks in Derry, N.H. Nearly six months ou Republican presidential hopeful Donald Trump remarks about Texas Gov. Rick Perry's glasses at his South Carolina campaign rally in In this photo taken Dec. 23, 2015, Republican presidential hopeful Ted Cruz speaks in Oklahoma City. With a deeper-than-ever split Republican presidential candidate Sen. Ted Cruz, R-Texas, speaks Tuesday, Jan. 12, 2016, during a campaign stop at Granite State I