2016 saw rise of populist outsiders. 2020 is showing limits of their appeal.

History, it appeared, was poised to repeat itself.

A political outsider with a simple, compelling message and the ability to draw huge, sign-waving crowds had taken the nation by storm. A populist cry of “us against them,” the little guy versus the elites, fueled the palpable concern of party regulars. 

Four years ago, it was Donald Trump who fomented a political revolution, took over the Republican Party, and captured the White House. Today, Bernie Sanders is seeking to do the same, from the left, to the Democrats. 

But 2020 is not 2016, and on Super Tuesday, Senator Sanders’ momentum hit a brick wall. Paradoxically, it may be President Trump’s success – at least in upending many of the norms of governance and public life – that hurt the democratic socialist senator’s cause, even as the same norm-busting mentality has energized the Sanders-loving left. 

Many Americans, in short, are exhausted. Democrats and disaffected Republicans seem almost desperate to vote out Mr. Trump. And for a significant portion of the party’s electorate, a Sanders nomination promises nothing so much as failure – most likely, many believe, losing in November. Even if Mr. Sanders were somehow to win the presidency, such a radical shift in agenda would be nearly impossible to implement, and could just lead to more upheaval. 

For liberal Democrats disappointed by the sudden revival of former Vice President Joe Biden – an avatar of the party establishment and now a frontrunner for the nomination – there’s a simple explanation: a desire for stability twinned with skepticism toward “revolution,” a term that still infuses Mr. Sanders’ rhetoric.  

“Something’s going on with Americans and Democrats above the age of 40, 45 that I don’t totally get,” says Teddy Smyth, a 20-something former staffer on the presidential campaign of Sen. Cory Booker of New Jersey. “I hate it, but it’s like a yearning for a return to normalcy as opposed to a gamble on a new vision, a new way of being American,” he says. 

Sen. Elizabeth Warren’s announcement Thursday that she is suspending her campaign now leaves Mr. Sanders and Mr. Biden as the only major Democratic candidates. Where Senator Warren’s supporters go is an open question; she’s a progressive, like Mr. Sanders, but has a more pragmatic streak. At press time, Ms. Warren had not issued an endorsement. 

Michael Bloomberg’s departure from the race Wednesday could help Mr. Biden, not only because the uber-wealthy former New York mayor endorsed the former VP but also because he’s keeping his campaign operation going to support Democrats in November up and down the ballot. Mr. Sanders has said he would reject such help, but Mr. Biden has not. 

Still, “Sandersism” – embracing Medicare For All, free college, higher taxes, and an aggressive approach to climate change – isn’t going away. Versions of the Sanders agenda have now become standard Democratic fare, a far cry even from the days of President Barack Obama, now seen by many as a moderate. 

Mr. Sanders “has brought back debates that seemingly were settled, like single-payer health care, exclusively government run,” says Bill Carrick, a veteran Democratic consultant in Los Angeles. 

It’s possible, political analysts say, that Mr. Sanders may become the “Barry Goldwater of the left.” Senator Goldwater, the Republican presidential nominee in 1964, lost in a landslide to President Lyndon Johnson. But his conservative and libertarian political philosophy lived on, forming the foundation of Ronald Reagan’s views and eventual rise to the presidency. 

The Arizona senator knew he was going to lose to Johnson, following the assassination of President John Kennedy, and decided, “I’m just going to run on principle,” says historian Michael Kazin of Georgetown University.  

Mr. Sanders exhibits the same sort of authenticity. “That’s why people like him,” says Professor Kazin, an expert on populism. “People think he’s saying what he really thinks.” 

Indeed, Mr. Sanders has been making the same arguments about inequality for decades, including eight years as mayor of Burlington, Vermont, in the 1980s. But back then, pragmatism prevailed over larger philosophical matters of social justice.

“There are obvious, real limits to what we can do,” Mayor Sanders told a Monitor reporter in 1984. 

As a senator, Mr. Sanders doesn’t have to govern anything, and can strike a more ideological stance. And over the years, on most legislation, he could be counted on as a reliable vote for the Democratic position, even as an independent. 

If Mr. Sanders were to win the Democratic nomination, now seen as less likely after underperforming on Super Tuesday, his views would spark a full-on national debate on socialism versus capitalism. 

Garry South, a longtime Democratic consultant based in Los Angeles, sees Mr. Biden as the likely nominee, and hopes that Mr. Sanders will work to unify his supporters behind him, doing everything he can to defeat Mr. Trump. 

“That’s what he claims he wants,” Mr. South says. “But it remains to be seen.”  

There’s no doubt that the Democratic electorate has moved to the left, Mr. South adds. No Democratic candidate today would think of voicing misgivings about same-sex marriage, for instance. 

But “it’s a real question in my mind whether Bernie Sanders has led that leftward drift or has simply tried to capitalize on it,” he says. 

He does not have many legislative achievements to his name. He gives passionate speeches, says Mr. South, but it’s kind of like the old saying, “There go my people and I must follow them because I am their leader.”

Indeed, Mr. Sanders was not a nationally known figure until he jumped into the 2016 Democratic nomination race – a decision, he said, that was driven by his view that Hillary Clinton should be challenged from the left, and after Ms. Warren declined to run. 

To the surprise of many, Mr. Sanders’ campaign took off, nearly overtaking Ms. Clinton, the establishment favorite. 

Now, many of those same Sanders supporters are urging him on again. But in 2020, with a more crowded Democratic field, he has failed to garner as big a percentage of the primary vote as he did four years ago. 

That has led to conspiracy theories, rampant on the web, that the Democratic “establishment,” including the Democratic National Committee, has been working to undermine the Sanders campaign. There is no evidence that that is true. In fact, the DNC changed its rules around superdelegates to accommodate Mr. Sanders’ concerns that they might try to take the nomination away from him at the Milwaukee convention in July. 

Mr. Sanders’ complaints about the party establishment and about the “corporate media” being biased against him echo Mr. Trump’s rhetoric at times – as does the rowdy behavior of both men’s most avid supporters.  

It’s no accident that some call Mr. Sanders the “Trump of the left.” Like the president, Mr. Sanders has tapped into concerns that more mainstream candidates failed to capture – particularly with younger voters. 

Shahrukh Shaikh, a young man from Fredericksburg, Virginia, who works at a Lowe’s home improvement store, said Tuesday he voted for Mr. Sanders because as president, he would cancel all student loan debt. 

“I’m drowning in student debt,” Mr. Shaikh said. “I can’t move out, nothing.” 

In the Highland Park neighborhood of Los Angeles, some waiting in line to vote on Super Tuesday were firmly for Mr. Sanders and others were still deciding how to go. But all said they’d vote for the Democratic nominee, including Mr. Biden. 

Margo Rust, porting her 10-month-old daughter in a snuggly, said she wasn’t enthusiastic about the former vice president. He would simply mean “more of the same,” while Mr. Sanders represents real change for a wide swath of everyday Americans – teachers, union members, farmers. 

Still, “I would hope that people can put specifics aside for a greater goal” of defeating President Trump, says Ms. Rust, who works as a freelancer in TV and film.  

Saul Prado, who runs his own handyman business, says Mr. Sanders has “started something appealing” – and in an ideal world, it would be great to get all the things he promises. But it’s not an ideal world, Mr. Prado adds. Leaning toward Ms. Warren (before her departure), he said he, too, would vote for Mr. Biden if it came to that. But he worries that some Sanders voters might not. 

“Sometimes they’re hard to pick apart from Trump voters,” he says. “They’re very dedicated. Almost cultish.”

If the party does fracture over its nominee, be it Mr. Biden or Mr. Sanders, that would pose a serious threat to the Democrats’ chances in November. 
 
“Divided parties never win,” Mr. Kazin says. “Ever.”

Staff writer Story Hinckley contributed to this report from Virginia.