1) It is not a question of whether the Democratic Party establishment will attempt to smear and destroy the Sanders insurgency if it manages to get more of a foothold but when and how they do so. (This has, of course, already begun, see, e.g. here and here.)
2) If history is any indication (c.f. the Dean scream, Hymietown, gonadal politics, etc.) the smear campaign in 1) is almost certain to be successful. Though they might not have to use it. (See 3).
3) Related to 2), according to two reputable press accounts, the NY State Democratic Party will not allow Sanders to compete in their primary. If that is so, Sanders won’t be able to acquire enough delegates for a win, and the campaign is effectively already over.
4) Once the campaign is over–either sooner or later–the question becomes what it always has been: In what direction will Sanders supporters (i.e. the principled left in the DP and outside) channel their activism? Will they be able to form a Syriza-style insurgency. Again, history does not make one optimistic, but this time could be different.
Of course, that’s the only question which matters.
John Halle blogs at Outrages and Interludes.