U.S. Republican presidential candidate Donald Trump gives a thumbs up to supporters as he is driven away...
U.S. Republican presidential candidate Donald Trump gives a thumbs up to supporters as he is driven away following a campaign town hall meeting in Derry, New Hampshire August 19, 2015. Trump said on Wednesday that when it comes to the polls in the crowded 2016 presidential race, "the only thing constant is Trump." REUTERS/Brian Snyder