There is no doubt the pols are biased.  They skew the selection of the public they poll to get the results they want.  If you want Bernie to loose a poll only poll old people.  They are shameless about it.  I do hope it is much higher but at the same time I know they have to keep the polls believable so they are limited to at most a 5-12 point spread.  I went conservative and said 5 points.