Workers construct a new home in Leyden Rock in Arvada, Colorado, U.S. August 30, 2016. REUTERS/Rick Wilking/File Photo

Mitt Romney talks to senior advisors Peter Flaherty, Beth Myers and Ed Gillespie ahead of his first debate with Barack Obama while flying on his campaign plane enroute to Denver. REUTERS/Brian Snyder

Rick Lazio walks over and challenges Hillary Clinton to sign a Freedom from soft money pact during their first 2000 Senatorial Debate in Buffalo. REUTERS/Richard Drew/Pool

Marco Rubio and Donald Trump speak simultaneously as they discuss an issue during the debate in Houston. REUTERS/Mike Stone

Hillary Clinton reacts as Bernie Sanders tries to hand her a piece of paper during a debate at the Brooklyn Navy Yard. REUTERS/Lucas Jackson

George W. Bush and Judd Gregg practice with Bush staff members for upcoming presidential debates against Al Gore, at Bush's ranch in Crawford. REUTERS/Jeff Mitchell

Barack Obama and Hillary Clinton wait before the South Carolina Democratic party's presidential candidates debate. REUTERS/Jim Bourg

Hillary Clinton listens as Barack Obama makes a point during a debate at Saint Anselm College in Manchester, New Hampshire. REUTERS/Brian Snyder/File Photo