Another year of the interloper?
It's a familiar plotline. An interloper runs for a party's presidential nomination and, with an anti-insider pitch, scores wins and near-wins in the first contests with vote pluralities.
His numerous opponents, fearful of antagonizing his enthusiastic supporters, launch attacks on one another that, predictably, hurt the attacker as well as the target.
Party establishment types, convinced the interloper is a sure loser in November, dither and tilt things mildly against him while trying to maintain the impression of fairness.
Candidates with no chance remain in the race, dividing the anti-interloper vote, hoping the interloper will collapse. But he doesn't, and even starts winning absolute majorities in late contests.
That's how Donald Trump won the Republican nomination in 2016, and so far, it's consistent with how Bernie Sanders is doing in this year's Democratic race.
Remember that Trump lost the Iowa caucuses to Ted Cruz, and that 65% of New Hampshire Republicans voted for somebody else. Sanders' performance so far is comparable: He had a lead in first- and second-round popular votes in Iowa, though he lost SDEs (state convention delegate equivalents) to Pete Buttigieg for a total of 564-562; and he won 26% to 24% over Buttigieg in New Hampshire.
The animus of the party establishment is even clearer than in 2016 -- with Iowa Democrats' bolloxing of the vote count and the repeated anti-Bernie bias of MSNBC and CNN. Former White House chief of staff Reince Priebus and Fox News handled Trump more gingerly four years ago.
Sanders looks hard-pressed to grow his core constituency (under-35s) as Trump did his (non-college grads) at this point four years ago, though in time, Trump's ceiling grew higher.
Sanders repels the highest-income Democrats, for obvious reasons. He got only 16% in affluent Bedford and Windham, two of the three New Hampshire towns he lost to Hillary Clinton in 2016. But the vote there -- and likely in the affluent precincts of contests to come -- was split between Amy Klobuchar and Pete Buttigieg, each of whom has constituency problems.
Buttigieg gets just about zero support from black voters, who cast more than 20% of Democratic ballots nationally and a majority in South Carolina. Many Democratic voters' sense of moral superiority derives from Democrats' near-unanimous support from blacks as well as the charge, based on thin to zero evidence, of Republicans' and Trump's racism. Buttigieg puts that at risk.