The chart on the right is from Nate Silver at FiveThirtyEight.com -- one of the most respected of the political prognosticators. He sees Sanders as having a 1 in 3 chance of winning the nomination. But he also sees the chance of a brokered convention as also being about 1 in 3.
Sanders has actually underperformed what he did in 2016 when it comes to winning delegates in Iowa and New Hampshire. He has less delegates after those two states than he did in 2016. He's going to have to do a lot better in the coming states if he's to get a majority of pledged delegates.
I'm not at all sure he can win a majority. And I think it very unlikely that he could win a brokered convention. Here's some of what Jennifer Rubin thinks in her op-ed for The Washington Post:
Sen. Bernie Sanders (I-Vt.) won the New Hampshire primary in such an underwhelming fashion — the second less-than-impressive outing in what should have been two of his easiest states — that it bears consideration as to whether he is actually best positioned to win the race.
Turnout in New Hampshire did not significantly increase from 2016 to 2008, even though there was no competitive Republican primary to draw independent voters. Sanders has twice now failed to produce a promised wave of voters. Without such an influx of voters, his electability argument crumbles. He must either appeal to a greater share of Democrats and independents than other candidates (which currently is not remotely the case), or he must bring in a flood of new voters (which also is not happening). In short, his ceiling is still stuck around 25 percent, just as it has been from the onset of the race. . . .
Given that the progressive wing (Sanders plus Warren) managed to get about 35 percent of the vote on Tuesday while the moderates totaled more than 52 percent, it is clear that the majority of the party is not eager to enter a political suicide pact with a self-described socialist promising a revolution.
As the front-runner, Sanders should also expect to take fire for breaking his promise to release all of his medical records. He is 78 and had a heart attack in October. The party has every right to know precisely the state of his health. If he wins the nomination without full disclosure, be prepared for the Trump campaign (which portrayed Hillary Clinton at death’s door when she came down with the flu) to portray Sanders with one foot in the grave. This is certainly a valid electability issue.
Democrats should not take Sanders lightly, but neither should he be portrayed as the favorite, let alone the shoe-in. The prognosticators have based their predictions on a slew of inaccurate suppositions (e.g. his vote totals would be higher, Buttigieg wouldn’t win Iowa). Perhaps it is time to watch the game as it plays out, understanding that this remains the most uncertain Democratic primary in recent memory.