The NY Times' Upshot blog has an evaluation of Bernie's path to the nomination and they believe he will come up short [Why Bernie Sanders’s Momentum Is Not Built to Last]. There's some analysis and a couple of graphs that show how important African American and "moderate" (their term) votes were in securing Obama the 2008 nomination. Their basic premise is that moderate/fiscally conservative primary voters will lean towards Clinton and Bernie will not have enough of a margin among liberals to overcome that.
But Mrs. Clinton still holds a huge lead among moderate and conservative Democrats — white and nonwhite alike. Whether Mr. Sanders can close the gap among these voters will determine the seriousness of his candidacy and whether he can pick up more delegates in other primaries. There aren’t many reasons to expect he will break through, and he certainly isn’t doing it yet.
Mr. Sanders could hope to do even better than Mr. Obama among liberals, but realistically there are limits. Mrs. Clinton is a liberal Democrat by any measure. Her favorability ratings among “very liberal” voters remain very good; the Quinnipiac poll, for instance, put them at 88 percent favorable and 8 percent unfavorable. Her advantage among women also helps. And this is leaving aside any of the other plausible reasons — electability, experience — for preferring Mrs. Clinton.
So Team Bernie, let's hear how you plan to overcome the hurdles the Times thinks litter his path :-)
PS. Personally, I think the biggest handicap Bernie has is age, I think a fair number of people will have concerns about electing a 74 year old to the presidency (McCain was 72 in 2008). I've heard many others express some concern about success in the general election given the "socialist" moniker, but I think Bernie can explain/cover that pretty well in debates and win many over.
Couple more snippets about Southern primaries and African American primary voters below.
There's a diary on the rec list which delves into the punditry's view that Bernie cannot rack up the kind of numbers Obama did among black voters.
The NY Times has a slightly different spin on it, they believe to win the Southern states in the primary (as Obama did), Bernie would need black support. They see that population as more conservative than the average primary voter and therefore less amenable to his appeal.
There were two types of these voters that allowed Mr. Obama to stay so close to Mrs. Clinton, and Mr. Sanders doesn’t naturally appeal to either one. First, Mr. Obama did well among moderates in affluent and well-educated areas, often with the help of self-described independents and Republicans. Nationally, Mr. Obama won independents by 12 points and Republicans by 8 points. Second, he won more than 80 percent of black voters, perhaps the least liberal demographic group in the Democratic Party.
But his problem with nonwhite voters is not properly understood as simply a problem of race. It’s primarily a problem with moderate and less educated Democrats, regardless of race, which happens to disproportionately affect his support among nonwhite voters.