Sanders will certainly face some heat for his desire to raise taxes on the middle class. What matters is his ability to explain that, in doing so, the middle class family will actually save money. This is the reality of a single-payer system, whether you're talking about healthcare or education - taxes go up, but the savings more than offsets that increase. If he isn't able to convey this fact in a succinct and convincing manner, he'll suffer for it, but so far he has proven to be pretty adaptable.
As for the "socialist" angle, there are many Americans who claim they wouldn't vote for a socialist.
http://www.gallup.com/poll/183713/socia ... aign=tiles
According to that poll, 41% of Democrats, 51% of independents and 74% of Republicans wouldn't vote for a person described as "socialist." On the other hand, over 66% of Americans under 30 say they don't care if a person describes as socialist, atheist, etc. Basically this reinforces what we already know: old people won't vote for socialists, young people will, and so the key for Bernie is driving the youth vote. I think he can do it. We are talking 70-90% of youth voters favouring him over Clinton. If that holds on a national scale, he's got a really decent shot, assuming turnout remains high.
