LAS VEGAS—In 2016, Sen. Bernie Sanders came within five points of beating Hillary Clinton in the Nevada caucuses, a stunning near-upset that, after a similar near-miss in Iowa, helped kickstart the progressive movement that has made him one of the most influential politicians in the country.

Four years later—and mere weeks after another hair’s-breadth loss in a caucus state he’d been favored to win—Sanders has won the Nevada caucuses outright, with a huge lead over his nearest competitor, Joe Biden. It cements his status as the undisputed frontrunner for the Democratic presidential nomination and positions him for a Super Tuesday performance that, his campaign says, could transform him from frontrunner to presumptive nominee.

In other words: Bernie’s got heat.

The odds were in Sanders’ favor in the weeks leading up to Saturday’s caucuses, after a closer-than-anticipated win in the New Hampshire primary and a debate in Sin City where insurgent billionaire Michael Bloomberg drew most of the fire that, under normal circumstances, would have been trained on the frontrunner.

Although the Nevada caucuses were far from smooth—thousands of early ballots were tossed out due to a lack of signatures—the state’s Democratic Party avoided the national humiliation endured by Iowa after that state’s untested reporting process fell apart on caucus night. But despite those hiccups, the Vermont independent’s lead was almost never in dispute on Saturday.

Sanders, like several of his fellow candidates, wasn’t even in Nevada when he gave his victory speech. Instead he spoke from Texas—a critical, delegate-rich Super Tuesday state.

“No campaign has a grassroots movement like we do, which is another reason we are going to win the election,” Sanders said at a packed rally in San Antonio. “In Nevada, I want to thank our rank and file union members.”

The “rank and file” reference was no accident.

Sanders’ win amounts to a strong rebuke of critics—both within the Democratic field and Nevada’s union-based political firmament—who said that his signature Medicare for All proposal would alienate members of the state’s powerful organized labor force, many of whom enjoy the spoils of decades of hard-fought contract negotiations that have won gold-plated healthcare plans for union members.

Although the influential Culinary Workers Union passed on formally endorsing a primary candidate in this cycle—and had implicitly criticized Medicare for All as a threat to its health care victories—Sanders appeared to be the favorite of rank-and-file union workers in Las Vegas.

“Since 2016 to here, I’ve followed Bernie,” said Hawi Baker, who works as a cleaner at the Bellagio Hotel and Casino and is a member of the Culinary Workers Union. Originally from Ethiopia, Baker said that she has been drawn to support Sanders because of his stance on universal health care, rather than in spite of it.

“For example, my husband, my kids’ dad, he don’t have insurance—he’s a truck driver,” Baker said. “But when he tried to get the insurance, it’s very expensive.”

Supporting Sanders, she said, was her way of supporting people whose employers do not have such robust health care programs.

“They need to support” universal health care, Baker said of the Culinary Workers Union. “They push hard for Biden, but I don’t know about Biden—I support Sanders.”

At a caucus precinct in the Bellagio’s Grand Ballroom for shift workers employed on the Las Vegas Strip, enthusiasm was stratospherically high for Sanders. Within the first few minutes of the first alignment period, wherein caucus-goers clump with fellow supporters of their chosen candidate in the hopes of hitting the 15-percent threshold for viability to obtain delegates, nearly two-thirds of the assembled voters had lined up on the ballroom’s right wall, chanting “BER-NIE! BER-NIE! BER-NIE!” at the supporters of the sole other candidate to reach viability: former Vice President Joe Biden.

Sanders won an outright majority of the precinct’s caucus-goers on the first alignment, and was awarded 32 delegates to Biden’s 19.

The former vice president finished in second place in Nevada, where a fleet of out-of-state precinct captains oversaw a weak realignment game. The night before, Biden’s final “Get Out the Caucus” event in a middle school gym drew a half-full crowd numbering around 350.

Biden’s campaign had been desperately hoping for a strong finish in the Silver State to springboard them to friendlier territory next weekend, and has emphasized that the former vice president would perform better as the primary calendar moved on to states with more diverse voting populations. But unlike his devastating finish in New Hampshire, Biden stuck around Nevada long enough to see the results come in with his feet still in the state.

Hours before the final results revealed the actual results, Biden came out to address his fans at the International Brotherhood of Electrical Workers Local 357 northeast of the Vegas Strip, pointing to his distant—and potentially temporary—second place showing in Nevada as a win.

Biden, welcomed onstage by precinct captains chanting “LET’S GO JOE!” and “FIRED UP AND READY TO JOE!” and, bewilderingly, “JoooooOOOoooo-oooo-OOOEEE” to the tune of “Seven Nation Army” by The White Stripes at a semi-engaged crowd, credited union workers with his strong-ish showing in Nevada.

“Y’all did it for me!” Biden said, with roughly 10 percent of precincts reporting, vowing to win in South Carolina one week from Saturday. “I think we’re in a position now to move on in a way that we haven’t been until this moment.”

“Next time I’ll come back to win this state outright” Biden added, without mentioning, even at that early hour, he was a distant second to Sanders. “We are alive and we are coming back and we are going to win.”

But in politics, as in Vegas, there is always someone younger and hungrier coming down the stairs after you—which means that Biden’s slide, mitigated by the Nevada caucus results or not, has provided an opening for the rest of the field to jockey for position.

The apparently foregone conclusion of Sanders’ victory meant that “victory” in Nevada was more about exiting the state with a respectable level of support and delegates. Former Mayor Pete Buttigieg, who has struggled with nonwhite voters, appeared to finish third in Nevada, but successfully replicated his Iowa caucus strategy of strong organizing in more rural, conservative areas of the state, where he successfully stripped away potential delegates from Biden and resurgent fellow Midwesterner Sen. Amy Klobuchar.

Still, he used his speech Saturday evening to take a swipe at Sanders.

“Senator Sanders believes in an inflexible, ideological revolution that leaves out most Democrats, not to mention, most Americans,” he said. “I believe we can defeat Trump and deliver for the American people by empowering the American people to make their own health care choices with Medicare for All who want it. Senator Sanders believes in taking away that choice.”

Klobuchar, meanwhile, failed to translate a twin pair of well-regarded debate performances into a successful caucus performance—an unsurprising result considering that until her surprise third-place finish in New Hampshire, the senator had a mere two staffers in the entire state.

Sen. Elizabeth Warren, whose successful vivisection of Bloomberg on the debate stage earlier in the week provided a crucial lifeline of donations and earned media coverage, appeared to be in fourth.