Donald Trump, president and chief executive of Trump Organization Inc. and 2016 Republican presidential candidate, smiles during a campaign rally at the Gerald W. Kirn Middle School in Council Bluffs, Iowa, U.S., on Sunday, Jan. 31, 2016. Donald Trump has overtaken Ted Cruz in the final days before Iowa's caucuses, with the fate of the race closely tied to the size of Monday evening's turnout, especially among evangelical voters and those attending for the first time. Photographer: Luke Sharrett/Bloomberg via Getty Images

Donald Trump, president and chief executive of Trump Organization Inc. and 2016 Republican presidential candidate, smiles during a campaign rally at the Gerald W. Kirn Middle School in Council Bluffs, Iowa, U.S., on Sunday, Jan. 31, 2016. Donald Trump has overtaken Ted Cruz in the final days before Iowa's caucuses, with the fate of the race closely tied to the size of Monday evening's turnout, especially among evangelical voters and those attending for the first time. Photographer: Luke Sharrett/Bloomberg via Getty Images