Sen. Bernie Sanders, I-Vt., strengthened his status as the clear front-runner in the Democratic presidential primary Saturday night with a decisive win in the Nevada Caucuses, tallying 46 percent of the vote with 50 percent of the results in -- a win that is worrying many members of the Democratic establishment that there may be no path to stop Sanders before the party's convention in July.

There were also reports of confusion at some precincts, which led former South Bend, Ind., Mayor Pete Buttigieg to send a letter to the Nevada Democratic party asking for more transparency, telling The Nevada Independent that a "razor-thin" margin for second place made a closer look at the results imperative.

Though it's not yet possible to project second place, third place and beyond with just 50 percent of the vote in, Sanders will catapult out to a lead in national convention delegates with momentum heading into South Carolina and Super Tuesday. As a result, former New York City Mayor Michael Bloomberg's campaign joined the many voices raising the alarm that Sanders could end up squandering Democrats' chance to unseat President Trump in November.

"The Nevada results reinforce the reality that this fragmented field is putting Bernie Sanders on pace to amass an insurmountable delegate lead," Bloomberg campaign manager Kevin Sheekey said in a Saturday night statement. "This is a candidate who just declared war on the so-called 'Democratic Establishment.' We are going to need Independents AND Republicans to defeat Trump – attacking your own party is no way to get started. As Mike says, if we choose a candidate who appeals to a small base – like Senator Sanders – it will be a fatal error."

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Echoing Sheekey's point was Democratic strategist James Carville, who said on MSNBC that it would be naive for Democrats to believe Sanders has enough potential voters to top President Trump and his electoral power.

"If you're voting for him because you think he'll win the election, because you think he'll galvanize heretofore sleeping parts of the electorate, politically, you're a fool," he said.

But Sanders' Nevada performance could be a sign that he is able to unite broad portions of the Democratic Party, something many were suspicious he could do before Saturday. He won a very diverse state with significant portions of the minority vote, and even did well with voters who identified as moderate and conservative. According to an NBC entrance poll, Sanders roped in 23 percent of the voters who identified as "moderate or conservative."

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At a Texas rally Saturday night, Sanders declared Nevada victory while stumping for votes in the diverse and delegate-rich Super Tuesday state where early voting is already underway.

"In Nevada, we have just put together a multi-generational, multi-racial coalition which is gonna not only win in Nevada, it's gonna sweep this country," Sanders said to a raucous crowd. "What we showed is that our volunteers are prepared to knock on hundreds of hundreds of thousands of doors, that no campaign has a grassroots movement like we do, which is another reason why we're going to win this election... We are going to win here in Texas, we are going to win across the country."

Meanwhile in Nevada, Buttigieg, who led the primary in delegates until Saturday night's Sanders win, warned that Democrats needed to be a big tent party in order to take back the White House in November.

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"I congratulate Sen. Sanders on a strong showing today knowing that we celebrate many of the same ideals," Buttigieg said. "But before we rush to nominate Sen. Sanders in our one shot to take on this president, let us take a sober look at what is at stake, for our party, for our values and for those with the most to lose. There is so much on the line. And one thing we know for sure is that we absolutely must defeat Donald Trump and everything that he represents in November."

With 50 percent of the Nevada returns in, Buttigieg has 15 percent of the vote, behind Sanders with 46 percent and former Vice President Joe Biden at 19 percent. The former mayor, who earlier this month "Saturday Night Live" joked was trying to present himself as the "#WhiteObama," is trying to elbow his way past Biden as the candidate with the best claim to the electability argument. That case is bolstered by the fact Buttigieg holds a lead in the yet-to-be-officially-called Iowa Caucuses and finished in a close second to Sanders in New Hampshire while Biden missed out on the top three in both states.

Nonetheless, Biden put a positive spin on his Nevada results and leaned on his supposed South Carolina firewall, where a majority African-American Democratic electorate still has him in the lead of the RealClearPolitics average of polls, with Sanders in a close second, billionaire Tom Steyer in third and Buttiegieg sitting in fourth place.

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"Y'all did it for me," Biden said to supporters in Las Vegas. "Now we're going down to South Carolina and win and then we're going to take this back."

Biden also criticized the media for calling his candidacy "dead," saying, "we're alive and we're coming back and we're going to win."

Behind Sanders, Biden and Buttigieg in Nevada, Massachusetts Sen. Elizabeth Warren secured 10 percent of the vote while Minnesota Sen. Amy Klobuchar and Steyer hovered around 5 percent, all with 50 percent of the total votes in.

Despite scattered reports of confusion at precincts, the Nevada Caucuses appeared to run more smoothly than the Iowa Caucuses, which saw the app the state Democratic Party planned to use to report results break down and several errors tabulating and reporting votes that led to a recanvass and now an ongoing recount.

The Nevada results have been slow to come in, however, with only half being reported on the night the voting took place. This was more than enough to declare Sanders the winner, but not enough to separate the other candidates bunched below him. The Nevada Democratic Party was likely saved from a lot of scrutiny by the fact Sanders won by such a large margin.

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But Buttigieg's campaign sent a letter to the Nevada Democratic Party alleging "material irregularities pertaining to the process of integrating early votes into the in-person precinct caucus results," raising the specter that Nevada's vote-counting process could go down a road similar to Iowa's.

The letter, sent late Saturday, was first reported by The Nevada Independent. It alleged that the Buttigieg campaign received "more than 200 incident reports" and identified specific errors, saying, "We do not know if these issues were corrected."

The slow trickle of results also complicates plans for any candidate who planned to claim they were the top moderate alternative to Sanders based on a relatively strong Nevada finish

Also, Nevada's results lend credence to a Bloomberg campaign internal memo that was leaked last week, claiming non-Bloomberg moderates need to quickly exit the race or risk Sanders running away with the nomination.

"As the race stands today, Sanders is poised to leave Super Tuesday with an over-400 delegate lead verses his next closes competitor [Bloomberg] -- a likely insurmountable advantage," the first bullet point of the Feb. 17 memo, first obtained by Axios, says. Fox News has confirmed the authenticity of the memo.

Bloomberg has not even been on the ballot in any of the first three contests of the Democratic race, but he has poured over $400 million into advertising in high-delegate Super Tuesday states, an investment that has allowed him to reach second-place in some national polls despite having no pledged delegates so far.

His virtually unlimited campaign war chest, financed by his personal fortune, looms large beyond this coming Saturday's South Carolina contest. Bloomberg seems to be the only Democratic candidate capable of financing a robust campaign against Sanders beyond Super Tuesday, especially if donations for other candidates start to dry up with Sanders taking a big lead.

Bloomberg also claimed that Sanders is Trump's preferred opponent in a Saturday night tweet replying to the president.

Trump tweeted: "Looks like Crazy Bernie is doing well in the Great State of Nevada. Biden & the rest look weak, & no way Mini Mike can restart his campaign after the worst debate performance in the history of Presidential Debates. Congratulations Bernie, & don’t let them take it away from you!"

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"Can he make it any more obvious who he wants to face in the general election?" Bloomberg responded.

But Bloomberg will have to avoid repeating his clunker of a Nevada debate performance at the South Carolina debate on Tuesday, which will be candidates' last chance to appear on a national stage with their competitors before Super Tuesday.

Less worried about Trump and more worried about their own election prospects, some moderate Democrats in Congress are freaking out over the prospect of Sanders at the top of their party's ticket in November, Fox News' Chad Pergram reported.

“It’s bad,” said one freshman Democrat from a swing district. “We are having conversations about how to deal with this.”

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“If [Sanders] is the nominee, we lose,” said one Democrat.

Rep. Stephanie Murphy, D-Fla., who flipped a seat from red to blue in 2016, is backing Bloomberg and says she is concerned about Sanders' building momentum.

“A Democratic primary which results in a nominee who is not a Democrat is troublesome,” said Murphy of Sanders.

Fox News' Chad Pergram, Kelly Phares and Tara Prindiville contributed to this report.