Remember that in the 2018 House Democratic primaries, candidates backed by Our Revolution (a Sanders-adjacent group), Justice Democrats (another progressive group) and Sanders himself often failed to win primaries. And a recent Gallup poll showed that a majority of Democrats wanted the party to become “more moderate” — a vague term, to be sure, but one that probably doesn’t refer to what Sanders is trying to do — rather than “more liberal” in the future.
And many of the Democrats who supported him in 2016 may not have been true, die-hard Sanders fanatics in the first place. Sanders won 43 percent of the overall Democratic primary vote in 2016. But, as FiveThirtyEight reported, 10 percent of Democratic primary voters went for Sanders in the primaries and someone other than Clinton in the general election. Some of these voters may have been Sanders fans who really would have voted for him but not Clinton in the general, but many of them were probably registering a protest vote against Clinton rather than an affirmative vote for Sanders. Sanders can’t count on those voters to all back him this time.
The younger and progressive voters who supported Sanders in 2016 still make up a substantial chunk of the party, but Sanders has more competition for these Democrats now than ever before.