Its now or never for Joe BidenJoe BidenButtigieg campaign claims ‘irregularities’ in Nevada caucusesPoll: Sanders leads 2020 Democratic field with 28 percent, followed by Warren and BidenMore than 6 in 10 expect Trump to be reelected: pollMORE.  
After coming in second in Nevada behind Bernie SandersBernie SandersSchiff blasts Trump for making ‘false claims’ about Russia intel: ‘You’ve betrayed America. Again.’Buttigieg campaign claims ‘irregularities’ in Nevada caucusesPoll: Sanders leads 2020 Democratic field with 28 percent, followed by Warren and BidenMORE, the pressure is on the former vice president to prove that he can win a presidential contest and become the centrist alternative to the progressive frontrunner for the partys presidential nomination.
To become a real rival to Sanders, aides and allies say he must win the primary this Saturday in South Carolina.
It would be a big victory for Biden that could restart a presidential campaign that was left sputtering about dismal performances in Iowas caucuses and New Hampshires primary earlier this month.
Team Biden hopes its fortunes improved with a second-place showing in Nevadas caucuses. Yet even that result left him far behind Sanders, the winner of that contest.
Hes gotta f*ckin win!, one longtime ally said of the South Carolina primary, where polls have for months shown Biden with a lead. All this other stuff about doing well is horseshit. 
Biden is now facing a serious challenge from Sanders, who has closed the gap in polls of South Carolinaa state Biden aides have labeled his firewall and is trying to win the state himself, which could push Biden out of the race.
A CBS News-YouGov poll out this weekend showed Biden in the lead with 28 percent support among Democrats and independent voters who are expecting to vote in the states primary. But Sanders has gained on Biden in recent weeks and received 23 percent in the new poll.
If Biden loses the Palmetto State, it will be curtains on his dreams of winning the presidency, and it will be a big problem for others trying to prevent Sanders from winning the nomination as well.
At this point, anything less than a win makes Sanderss momentum almost insurmountable, said Basil Smikle, a former aide to Hillary ClintonHillary Diane Rodham ClintonSchiff blasts Trump for making ‘false claims’ about Russia intel: ‘You’ve betrayed America. Again.’The problem with Trump’s Middle East peace planTrump’s Intel moves spark Democratic furyMORE who also served as the executive director of the New York State Democratic Party. 
Smikle said that a Sanders win in South Carolina with substantial support from black voters would boost his coalition and do what Iowa did for former President Barack ObamaBarack Hussein ObamaRahm Emanuel: Sanders is ‘stoppable’5 takeaways from the Nevada caucusesEx-CIA chief calls Trump intel shakeup a ‘virtual decapitation’ of the intelligence communityMOREs 2008 campaign. 
It can brand Sanders campaign as multi-generational and multi-racial movement with some ability to siphon some Obama-Trump voters from the president, he said.
Sanders aside, Biden aides and allies say they feel good about the current state of the race after what they saw as a bounceback perfornace in Nevada.
For the first time, Biden did come ahead of the other centrists in the race. Former South Bend, Ind., Mayor Pete ButtigiegPeter (Pete) Paul ButtigiegButtigieg campaign claims ‘irregularities’ in Nevada caucusesPoll: Sanders leads 2020 Democratic field with 28 percent, followed by Warren and Biden9-year-old asks Buttigieg how to be strong and tell people he is gay tooMORE had defeated him in New Hampshire and Iowa, while Sen. Amy KlobucharAmy Jean KlobucharPoll: Sanders leads 2020 Democratic field with 28 percent, followed by Warren and BidenSanders has wide leads in two of three battleground states: surveyDemocrats: It’s Trump’s world, and we’re just living in itMORE (D-Minn.) finished ahead of the former vice president in New Hampshire.
Biden also got a boost from former New York City Mayor Mike Bloombergs disastrous performance in last weeks presidential debate.
They feel vindicated in a way because they kept saying that Pete Buttigieg wouldnt do well past the first two states when he hits more diverse terrain and Mike Bloomberg seems to have flamed out fast after the disastrous debate, said one longtime ally who is regularly in touch with the campaign.
Biden aides and allies also say they will get a boost from the endorsement of House Majority Whip Jim ClyburnJames (Jim) Enos ClyburnClyburn: Nevada will have ‘somewhat of an impact’ on South CarolinaSunday shows preview: 2020 candidates look to South CarolinaClyburn on Russian election meddling: ‘There is something going wrong’MORE (D-S.C.) who carries tremendous sway in the Palmetto State. 
Its the best thing that happened to us in weeks, the second ally said. By a long shot. 
In an interview on Face the Nation on Sunday Biden he expects to do well in South Carolina. 
But the former vice president pushed back on the notion that the state was his firewall. 
You said its my firewall, Ive never said that, he told host Margaret Brennan. Ive said Im going to do well there. 
The former vice president will spend his time crisscrossing the state this week aiming to solidify his support with black voters who he is counting on to be the backbone of the campaign.
Democratic strategist Joel Payne, who served as the director of African American Paid Media on Clintons 2016 presidential campaign, said it is critical for Biden to run up the score on Samders with black voters in South Carolina.
Not only would that undercut Sanderss chances at running away with the nomination but it would harm the other moderates in the race like Buttigieg and Klobuchar as well as build some pressure on them to bow out going into Super Tuesday, he said.  
Buttigieg, Klobuchar, Biden and Bloomberg all appear to be competing for some of the same voters, while Sanders, to his credit and benefit, has been boosted by loyal supporters in each early-contest state.
Democratic strategist Michael Trujillo said that Biden needs a solid debate performance on Tuesday night to build momentum for the weekend vote in South Carolina, and for the 14 contests that follow on Marc h 3.
With people early voting in many Super Tuesday states now, a debate victory is in many ways more important than a major South Carolina win, Trujillo said. Biden has to make sure Bernie leaves Tuesdays debate in a worse shape then how he entered it.
The second Biden ally said the former vice president agreed that if Biden can walk away with a solid debate performance and doesnt make any major gaffes, hell be on his way to victory. 
But Payne said Biden cant just win. He needs a solid victory. 
Meaning it needs to be closer to a 10-point win than a five-point win, he said.
The first Biden ally said Biden just needs to win. Lets not move the goal post, the ally said. A win is a win.