With the passing of Antonin Scalia, the most important qualification for the Democratic nominee is now, if it wasn't before, electability. No one should be playing craps with their vote this year. If you really give a shit about liberal policies and laws then you won't take a chance by nominating McGovern II.
There is no evidence that Bernie could draw one vote from the troglodytes but there is plenty that he might drive away Democratic votes.
I hope folks will look at history before making what could be a disastrous decision. Please nominate a Democrat that can win the WhiteHouse. Bernie is not that person.