For one thing, this would have been very hard to predict when the race got underway in earnest several months ago. Hillary Clinton, who won the New Hampshire primary eight years ago, appeared to have an insurmountable lead over a 74-year-old socialist senator, who was believed to be running as a protest candidate, simply looking for a platform for his ideas. And yet, as the dust settles, Sanders appears to have finished with a roughly 22-point victory.
For another, consider that margin in a historical context. Among New Hampshire Democrats, the biggest win ever for a non-incumbent was Michael Dukakis' 16-point victory in 1988. Sanders defeated that record easily. In fact -- here's the really amazing part -- Sanders' 22-point win is actually larger than some of the Democratic primaries in which an incumbent Dem president faced a challenger: Jimmy Carter won by 10 points in 1980 and Lyndon Johnson won by 8 points in 1968.
Exit polls offer us some sense of how the Vermont independent pulled it off.
Values and demographics shaped the strong support Bernie Sanders received Tuesday in New Hampshire, according to the NBC News Exit Poll of Granite State Democrats. The Vermont senator won 83 percent of millennial voters under the age of 30. He also won 66 percent of voters who describe themselves as very liberal, and at the same time took 72 percent of self-described independents.
That last point is of particular interest. Among New Hampshire Democrats, Clinton and Sanders actually tied, but independents voted in the primary and propelled Sanders to his record victory.
Having set the stage, let's now consider the What It All Means question.
For Sanders' supporters, it's quite simple: the senator's easy win in New Hampshire, coupled with a strong, second-place showing in Iowa, means Sanders has the momentum he'll need to win the Democratic nomination.
And that may yet happen. But some caution is in order.
Following up on our post-Iowa coverage, FiveThirtyEight's Nate Silver published a piece back in July noting that Sanders is strongest in states where the universe of Democratic voters is very white and very liberal. Based on previous performance, that means the three best states in the Union for the senator are, in order, Vermont, New Hampshire, and Iowa.
This is no small detail. It means that, other than his own home state, Iowa and New Hampshire are quite literally the two strongest states in the nation for Sanders.
Sanders and his capable campaign team know exactly what they have to do as the race shifts to less-friendly terrain -- expand the senator's base of support, connect with constituencies that have not yet been as receptive to his message, etc. -- but pulling it off is much easier said than done.