COUNCIL BLUFFS, IA - JANUARY 31:  Detail of Republican presidential candidate Donald Trump's hair as he signs autographs after a campaign rally at the Gerald W. Kirn Middle School on January 31, 2016 in Council Bluffs, United States. Trump and other presidential hopefuls are in Iowa trying to gain support and crucial votes for tomorrow's caucuses.  (Photo by Christopher Furlong/Getty Images)