"Sanders didn't stand a chance as a commie pinko against the Republican propaganda mills." Speculation.

"There was a debate last spring, when the Sanders/Clinton race was at its most heated, as to whether Bernie Sanders’ consistently out-polling Hillary Clinton was to be taken as a serious consideration in favor of his nomination. Before, during and after the race was competitive, this was the Vermont senator’s strongest argument: He was out-polling Trump in the general election by an average of 10 or so points, whereas Clinton was only slightly ahead. His favorables were also much higher, often with a spread as much as 25 points."

http://www.commondreams.org/views/2016/11/13/polls-showed-sanders-had-better-shot-beating-trump-pundits-told-you-ignore-them