Rival candidates have just a week to stop Sen. Bernie Sanders Bernie SandersNYT editorial board remembers Ginsburg: She 'will forever have two legacies' Two GOP governors urge Republicans to hold off on Supreme Court nominee Sanders knocks McConnell: He's going against Ginsburg's 'dying wishes' MORE if they hope to prevent the Independent from Vermont from taking the party’s presidential nomination.

Sanders is the undisputed front-runner in the race after his thumping victory in Nevada’s caucuses on Saturday.

His current trajectory is set to carry him to at least a top-two finish in South Carolina’s primary Saturday. From there, he looks likely to roll through Super Tuesday on March 3, harvesting huge numbers of delegates from California and other large states.

ADVERTISEMENT

It is eminently plausible that, by the end of that night, Sanders will have jumped out to a delegate lead that none of his rivals can reel in — especially given the likelihood that more than a half-dozen other major candidates remain in the race.

It’s a prospect that thrills his supporters — and horrifies Democrats who fear the democratic socialist would lose a general election to President Trump Donald John TrumpUS reimposes UN sanctions on Iran amid increasing tensions Jeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Trump supporters chant 'Fill that seat' at North Carolina rally MORE.

Sanders has a real chance of winning the South Carolina primary. Such a result would likely mark the de facto end of former Vice President Joe Biden Joe BidenMomentum growing among Republicans for Supreme Court vote before Election Day Trump expects to nominate woman to replace Ginsburg next week Video of Lindsey Graham arguing against nominating a Supreme Court justice in an election year goes viral MORE’s campaign — and give Sanders unstoppable momentum going into Super Tuesday.

“If he wins South Carolina, the train has left the station,” said one Democratic strategist who asked for anonymity to discuss the state of the race.

The Vermont senator’s strength in California is especially important. There are 415 delegates up for grabs in the Golden State — the single biggest prize in any primary. Even though the state’s primary is not winner-take-all, sizable margins for Sanders could catapult him way ahead.

Sanders currently has an 11-point lead in California, according to the RealClearPolitics polling average.

ADVERTISEMENT

The speed at which Sanders has moved into a dominant position has left many more moderate Democrats both disconcerted and panicked.

There is not a great deal of empirical evidence to support their charge that he is unelectable. In polls that measure hypothetical match-ups with Trump, Sanders does not perform notably worse than other candidates.

But Democrats who are skeptical of Sanders had their nerves jangled again Sunday by comments he made about Fidel Castro, the late Cuban president.

Sanders was asked during a CBS “60 Minutes” interview about his past praise for elements of Castro’s government, and essentially repeated his view.

“When Fidel Castro came to office, you know what he did? He had a massive literacy program. Is that a bad thing? Even though Fidel Castro did it?” Sanders said — even though he also condemned Castro’s authoritarianism.

Rivals including Biden and former New York City Mayor Mike Bloomberg blasted Sanders for the remarks. Democratic members of Congress joined the chorus of condemnation — Rep. Debbie Mucarsel-Powell Debbie Mucarsel-PowellHispanic Caucus members embark on 'virtual bus tour' with Biden campaign Florida Democrat introduces bill to recognize Puerto Rico statehood referendum Mucarsel-Powell, Giménez to battle for Florida swing district MORE (D-Fla.) called the comments “absolutely unacceptable” — and the Democratic Party of Florida also distanced itself.

The furor was important because, to some, it raised new questions about Sanders’s ability to carry the crucial state of Florida, where about 7 percent of the population is Cuban American.

The Sunshine State has been decided by margins of 3 percentage points or less in the past three presidential elections.

Of course, there are plenty of more general concerns expressed by centrist Democrats.

Rahm Emanuel, the former mayor of Chicago, told ABC’s “This Week” on Sunday that Sanders was “stoppable” in his march toward the nomination.

“But I would say this: The moderates need to coalesce around one person,” Emanuel added.

There is no sign that is about to happen.

ADVERTISEMENT

Democrats who have hoped that the party would opt for a more centrist nominee than Sanders have been frustrated to see several candidates split moderate support, including Biden, Bloomberg, Sen. Amy Klobuchar Amy KlobucharThe Hill's Morning Report - Sponsored by The Air Line Pilots Association - White House moves closer to Pelosi on virus relief bill EPA delivers win for ethanol industry angered by waivers to refiners It's time for newspapers to stop endorsing presidential candidates MORE (D-Minn.) and former South Bend, Ind., Mayor Pete Buttigieg Pete ButtigiegBipartisan praise pours in after Ginsburg's death Bogeymen of the far left deserve a place in any Biden administration Overnight Defense: Woodward book causes new firestorm | Book says Trump lashed out at generals, told Woodward about secret weapons system | US withdrawing thousands of troops from Iraq MORE (D).

Meanwhile, progressives have largely coalesced around Sanders as Sen. Elizabeth Warren Elizabeth WarrenBiden's fiscal program: What is the likely market impact? Warren, Schumer introduce plan for next president to cancel ,000 in student debt The Hill's 12:30 Report - Presented by Facebook - Don't expect a government check anytime soon MORE (D-Mass.) has underperformed expectations.

The prospect of one or more of the remaining major candidates dropping out before Super Tuesday is undercut by a basic fact. They’re not in the race to thwart Sanders specifically; they are in it to try to win the White House themselves.

For Sanders supporters, events are unspooling almost exactly as they predicted.

“There is nothing you can point to that would suggest anything other than that he will maintain strength, fundraise at a gargantuan scale and continue to get more delegates,” said Jonathan Tasini, a Democratic strategist who supports Sanders but has no role in his campaign.

Alluding to Sanders’s strength in California and elsewhere, Tasini suggested that Sanders could be in an almost impregnable position by the next date for multiple primaries. Six states vote on March 10.

ADVERTISEMENT

“By the time we get to the next wave — Super Tuesday Two — no one will be able to catch him,” Tasini predicted.

Unaligned strategists argue that, even now, there is a tendency to underestimate Sanders’s position.

“If Joe Biden or Elizabeth Warren had done what Bernie just did, there would be no hesitation. They would be the front-runner,” said one such strategist, Joel Payne.

Payne added that the desperate search on the part of some Democrats for a way to derail Sanders was simply another testament to his strength.

“If there is an ‘Anybody but …’ campaign, go with the ‘but’,” Payne said. “It probably means that the ‘but’ person is formidable enough that they are going to be hard to stop.”

The Memo is a reported column by Niall Stanage, primarily focused on Donald Trump’s presidency.