His very unwillingness to be confined by existing voter attitudes, as part of a long-term strategy to change them, is both a very valuable contribution to the democratic dialogue and an obvious bar to winning support from the majority of these very voters in the near term.
And as much as I wish it weren’t the case, we are still very much in that near term. As the intriguing challenger to Clinton, Sanders gets a pass in the current campaign. The media are very happy to have a race to cover where they feared — yes, feared — there would not be one. While Republican officeholders cannot be seen to be kind to a socialist, conservative commentators and media will be joining Kristol in touting Sanders’ heretofore unnoticed virtues. Meanwhile, Democrats — especially those who, like me, share most of Sanders’ policy views and do not have an allergic reaction to the word “socialism,” even if we disagree with it as an economic theory — are reluctant to be critical of someone who is an ally.
I know from past experience I will be criticized for writing here about making such tactical and strategic arguments. Some of my liberal allies will object that precisely because Sanders will not win the nomination, it is unnecessary — even unseemly — for me to write as I just have. But the critical point — that many of my fellow and sister Democrats understand but would rather not be caught saying — is that one clear result of a long Clinton-Sanders nomination contest would be that some of his vulnerabilities will accrue to her.