LAS VEGAS, NV - OCTOBER 13:  (L-R) Democratic presidential candidates Jim Webb, u.s. Sen. Bernie Sanders (I-VT), Hillary Clinton, Martin O'Malley and Lincoln Chafee take part in presidential debate sponsored by CNN and Facebook at Wynn Las Vegas on October 13, 2015 in Las Vegas, Nevada. The five candidates are participating in the party's first presidential debate.  (Photo by Joe Raedle/Getty Images)