Ben Carson

U.S. Republican Ben Carson's 2016 presidential bid was thrown into chaos on the last day of 2015 when his campaign manager and some 20 other staff members quit amid infighting, dropping poll numbers and negative media coverage. 

Ben Carson has placed first in a recent national Republican presidential primary poll, pushing Donald Trump into second place for the first time since June. 

Carson, a retired neurosurgeon, received 26 percent of the support in the New York Times/ CBS News poll released on Oct. 27 morning. 

Republican presidential hopeful Ben Carson said on Sept.20 no Muslim should be president of the United States, adding a new twist to a controversy roiling the party's White House nominating race.