Bernie Sanders isn’t the sole alternative to Hillary Clinton any more. Photo: Ethan Miller/Getty Images

In 2016 Senator Bernie Sanders was a reasonably close runner-up to Hillary Clinton for the Democratic presidential nomination. By losing that contest he evaded the blame for an unexpected loss to Donald Trump, and was also able to keep his political organization intact beyond Election Day. With Barack Obama’s term wrapping up, moreover, Sanders looked suddenly prescient in taking left-bent policy positions that the president did not share but was no longer in a position to proscribe. And his most intense following in the primaries was among young voters that seemed to bond with him like baby ducks, following him henceforth as their political hero.

But as the 2020 presidential contest begins to unfold, Bernie Sanders is something of an afterthought, if not quite a has-been. Instead of initially clearing the field of major rivals like Hillary Clinton did in her return to the campaign trail after finishing second to Barack Obama in 2008, Sanders faces a historically large list of competitors if he runs. In scattered national polling, he’s mired in the teens, well below Joe Biden and barely leading Beto O’Rourke. He’s not doing much better in the early states of Iowa and New Hampshire, where he invested so much time and so many resources in 2016. The candidates that he and his Our Revolution organization backed in the 2018 midterms had a mixed record at best.

As the New York Times suggests, Sanders seems to have lost his mojo:

Mr. Sanders may have been the runner-up in the last Democratic primary, but instead of expanding his nucleus of support, in the fashion of most repeat candidates, the Vermont senator is struggling to retain even what he garnered two years ago, when he was far less of a political star than he is today.

What’s happened to Sanders? I would cite six factors contributing to the decline in his support:

1) A lot of his 2016 support was due to his lonely resistance to a Hillary Clinton “coronation.” Yes, many Sandernistas were attracted to their candidate’s left-bent policy ideas, particularly tuition-free college and single-payer health care. But his candidacy was basically a catchment for Democrats and Democratic-leaning independents who had some reason for not supporting Hillary Clinton. Indeed, many were motivated less by ideology or policy than by the perception that a corrupt “Establishment” was forcing the front-runner on voters. He’s lost all that energy, at least until such time as an “Establishment” favorite emerges and dominates the field.

2) His message and policy positions are no longer all that distinctive. As the Times puts it, Sanders is “the victim of his own success” by modeling an agenda that others are now adopting. In 2016 he stood alone in advocating Medicare for All, a proposal that Clinton actively and vocally opposed. Now potential 2020 candidates Cory Booker, Kirsten Gillibrand, Kamala Harris, and Elizabeth Warren support the same proposal — and so, more obviously, do 2016 Sanders supporters and possible 2020 rivals Jeff Merkley and Tulsi Gabbard. If, as is often said, Sanders has helped move the Democratic Party to the left, then he’s now part of a larger progressive band and not so much its conductor.

3) He’s mighty old. Yes, at 77 Sanders is just three-and-a-half years older than he was when he launched his 2016 effort, as is his putative general election opponent Donald Trump. But there’s something a bit daunting about a presidential candidate who will turn 80 during a first term in office. It’s a problem he shares with Joe Biden, though even the former vice-president is younger than Bernie. In a large field of candidates, there are plenty of options that don’t involve consulting actuarial tables or worrying about a disabled or even deceased nominee.

4) The movement he founded is ready for a Joshua generation. Precisely because of his success and the emergence of like-minded progressives (and even self-proclaimed socialists), Sanders can be respected yet marginalized as the Moses who founded a movement that now needs Joshuas — a new generation of leadership. Sarah Jones articulated this viewpoint last year in calling on Sanders to eschew another presidential campaign:

If this resurgent left is to survive and flourish, it needs to prove that it can work without a personality to prop it up. This won’t be news to longtime activists on the left, who organize mostly in obscurity on behalf of a constellation of progressive causes. It won’t be news to Sanders either, who was an activist long before he was a politician.

5) He’s a white man in a party increasingly dominated by women and people of color. Sanders allegedly has a special appeal for the white working-class men that Democrats have been losing for decades. But he also showed some weakness in the 2016 primaries in relating to women and minorities, who ultimately lifted Clinton to the nomination. To the extent that Sanders is no longer ideologically unique, Democratic primary voters may prefer someone who is not only younger, but is more representative of the Democratic electorate itself.

6) His supporters are all over the place. As noted above, some 2016 Sanders supporters may actually run against him. Others are already involved in rival proto-campaigns like O’Rourke’s. And as the polls indicate, many rank-and-file Sandernistas are looking elsewhere. Given his other issues, it wouldn’t take too many false steps or setbacks to send a 2020 Sanders candidacy into a quick oblivion. It’s not like Sanders fans have nowhere else to go.

The key question at this early stage is whether Sanders will persist in thinking he’s as indispensable to his cause as he was when he improbably took on an “unbeatable” Hillary Clinton. Political history is littered with ideological prophets who were eventually dishonored in their own political homes. If Bernie Sanders has to fight to hold onto the mantle of progressive leadership, his time has surely past.