LAS VEGAS — Bernie Sanders is the favorite. Amy Klobuchar is untested, but riding a wave of momentum. And Joe Biden desperately needs to turn his campaign around.

Beyond that, even Democrats deeply familiar with Nevada are hesitant to make any sort of prediction ahead of Saturday’s caucuses, where a cloud of certainty is hanging over a contest that has taken on a greater sense of urgency after the leading candidates emerged closely divided from the first two states.

“Usually a combination of polling history and understanding the local dynamic will give you a good sense of how things will shake out by this point,” said Mark Mellman, a longtime pollster for former Nevada Sen. Harry Reid and the president of Democratic Majority for Israel, which has run ads attacking Sanders. “But this race is really wide open. There are people with upward momentum, and people with downward momentum.”

After spending the bulk of the past few months focused on Iowa and New Hampshire, the Democratic presidential contenders tried to make up for lost time over the weekend, campaigning relentlessly in Nevada as thousands of voters began to cast ballots early.

In a still-jumbled race, any level of unexpected success for the top candidates could give them a boost heading into the South Carolina primary at the end of the month — and, perhaps more critically, the delegate-rich contests of Super Tuesday in March.

“As all of you know, we won the popular vote in Iowa,” Sanders said during a Saturday morning rally in a suburban high school, drawing raucous cheers. “We won the New Hampshire primary. With your help, we can win here in Nevada. We are together going to win the Democratic nomination. And together we’re going to defeat Trump and transform this country.”

The unusual volatility in Nevada is the result of several factors, local Democrats say. After his strong showings in the first two contests, Sanders is widely viewed as the front-runner in the state, though not an overwhelming one, thanks to his committed base of support.

The two candidates that finished the closest behind the Vermont senator in New Hampshire, Pete Buttigieg and Klobuchar, also have had the least support among African American and Latino voters, who make up a significant share of the state’s electorate.

Meanwhile, the candidate who was supposed to have the most support with those voters, Biden, slumped to disappointing fourth- and fifth-place finishes in Iowa and New Hampshire, respectively.

And then there are voters like William Spielberg, a 44-year-old electrician from Las Vegas who had not yet mind up his mind who to support even as he lined up to vote early Sunday.

“There are so many candidates,” said Spielberg, who added that he was probably leaning toward Sanders. “We’ve got a lump sum of them.”

Late-deciding voters have been a hallmark of the still-young Democratic race: In Iowa, entrance polls showed more than one-third of Democrats made up their minds in the days before the caucuses. In New Hampshire, exit polls found that half of the voters said they decided “in the last few days” before the primary.

“The communication I’m having with folks reveals to me the possibility of anyone doing well here,” said Aaron Ford, Nevada’s Democratic attorney general. “There are lots of minds that haven’t been made up.”

Polling in the state will do little to clarify the state of the race. Only one poll has been released this month from Nevada, which showed Sanders leading with 25% support.

Nevada’s Spanish-language voters have always made the state a challenge to poll, Mellman said, as has an electorate whose concentration in the service industry means unconventional work hours that pollsters must adjust for. On top of that, turnout is typically harder to predict in caucuses compared to traditional primaries.

“You can poll in any state,” Mellman said. “The question is whether you can accurately poll in this state.”

Klobuchar has experienced a surge of momentum since her strong performance in the last debate, finishing a surprising third in New Hampshire and announcing Sunday that her campaign had raised $12 million in the nine days since the debate.

But in Nevada, a candidate who has thus far drawn most of her support from white voters faces a much different electorate, as she was reminded Saturday.

At a Black History Month festival in Las Vegas, Klobuchar was introduced by Nevada state Sen. Pat Spearman, who said she had met Klobuchar only a few days earlier. Klobuchar herself acknowledged that many in the audience might not know her, reciting basic details of her biography like her grandfather’s career as an iron-ore worker or the inspiration she drew from the late Minnesota Sen. Paul Wellstone.

“In case you don’t know as much about me, this is my background,” she said.

A February poll from Quinnipiac University found Klobuchar did not have any support nationally among black voters. That deficiency was less of a problem in Iowa and New Hampshire, two overwhelmingly white states, but could hurt her in a state where 41% of the Democratic electorate was non-white, according to an entrance poll of the 2016 Nevada caucuses.

Klobuchar did craft a message for the event, praising Nevada for being the first state to ratify the 15th Amendment, which guarantees the right to vote for citizens regardless of race. She also name-checked former Georgia gubernatorial candidate and civil rights activist Stacey Abrams, and mentioned recent attacks against minority communities.

“When there was that murder in that church in Charleston, when the white supremacist went in there and killed the worshippers, what affected those people in their lives, affected all of us,” Klobuchar said, referencing the 2015 murder of nine African Americans at the Mother Emanuel African Methodist Episcopal Church. “When a rabbi in New York gets people stabbed in his home, what affected them affects us all. When there was a bombing in a mosque in Minneapolis, what affected them, affects all of us.”

Klobuchar was politely received during her speech, and when those in the audience shook her hand afterward, they wished her campaign well.

But when Biden appeared at the same event a half-hour later, the reaction was much different. Attendees swarmed the former vice president for selfies, and the event’s emcee joked that he wanted Biden to send a jet to pick him up for next year’s presidential inauguration.

For his part, Biden made a concerted effort over the weekend to rebut criticism his personal performance on the campaign trail has undercut his appeal.

Some voters were still skeptical.

Shortly into his speech Friday at an event in Henderson, the former vice president said he was ditching the teleprompter stationed in front of him, grabbed a microphone, and started riffing about health care reform and reducing gun violence while pacing in the front of the room.

A day later, Biden delivered a fiery speech at a Clark County Democratic Party event, reiterating his campaign would perform better in a diverse state like Nevada than it had in Iowa and New Hampshire, while condemning the National Rifle Association.

“I’m not going to rest until we get assault weapons off the street, high-capacity magazines outlawed and off our streets,” Biden said, his voice elevated as he invoked the 2017 mass shooting in Las Vegas that left nearly 60 people dead. “And until we finally, finally, finally, we take on gun manufacturers for the carnage that they have caused.”

The speech was well-received inside the room, where a boisterous few dozen attendees chanted “Joe” and held up his campaign sign.

“You can go through the decades and can see the decency, the integrity, the honesty,” said Barbara Bell, a 64-year-old retiree who attended Biden’s event in Henderson and made clear there was “no question” she’d caucus for Biden. “He’s a regular Joe.”

Still, even some who attended Biden’s events said they weren’t sure they’d support him and questioned whether Democrats needed new leadership.

“I think he’s missed his moment. I really do,” said Ansley Truitt, a 69-year-old Las Vegas resident who attended the Black History Month festival. “I think he has some political baggage that’s going to hurt him.”

Truitt said he was considering supporting Sanders or Klobuchar, the latter of whom he shook hands with at the festival.