Democratic presidential candidate former Vice President Joe Biden, right, and his wife Jill attend a primary election night…
Democratic presidential candidate former Vice President Joe Biden, right, and his wife Jill attend a primary election night rally March 3, 2020, in Los Angeles.

WASHINGTON - Mainstream Democrats were rejoicing over Joe Biden's rousing Super Tuesday performance that bolstered his bid for the Democratic presidential nomination, easing worries over the havoc they fear awaits down-ticket moderates should Sen. Bernie Sanders become the party's standard-bearer.
   
 “He can hurt the whole Democratic Party,” Rep. Emanuel Cleaver, D-Mo., an early backer of the former vice president, said Wednesday about Sanders, the self-described socialist from Vermont. “And our single most significant cause celebre is removing Donald Trump. He can hurt that.”
    
Now, Cleaver said, “I think we're going to win.”
    
The remarkably abrupt coalescing of the once unwieldy Democratic presidential field into essentially a two-person race was underscored Wednesday as Mike Bloomberg, the former New York mayor, ended his costly bid for the nomination and endorsed Biden. Bloomberg had spent over $500 million of his own money, a huge sum in politics but relative trifle for the multibillionaire, but proved to be barely a blip during the contest.
    
“What we faced a week ago was the moderate-progressive movement or base in Virginia splitting four ways'' among Democratic contenders, said Rep. Don Beyer, D-Va. Beyer jumped on Biden's bandwagon only this week after former South Bend, Indiana, Mayor Pete Buttigieg abandoned his own campaign.
   
“`I'm really encouraged by it and I feel much more optimistic now about being able to keep the House, take back the Senate and win the presidency,” said Beyer.
    
Yet while Biden won at least eight of the 14 Super Tuesday states, including delegate-rich Texas and a broad swath of the South, Sanders demonstrated his strength by winning California, the nation's biggest state. And there were no signs that the rift between Democratic moderates and liberals that's fueled their presidential contest has been healed.
    
Indeed, it remained unclear how long it will take for Democrats to decide which of their two front-runners will grab the nomination. Progressive Sanders supporters were showing no signs of surrender for a candidate they still insist will energize throngs of young voters and drive the party to a victory in the fall.
    
“I think that there was a lot of scare put out there about what a Bernie Sanders presidency might do,” said Rep. Pramila Jayapal, D-Wash., who's endorsed the senator. “People really have to think about whoever the nominee is, have to think about how we inspire.”
    
With Sanders having also won at least three other states on Tuesday, Jayapal said, “I think that this is going to be a hot race until the end.”
    
Another illustration of the left's defiance came from Jessica Cisneros, a 26-year-old immigration attorney who narrowly missed toppling eight-term incumbent Rep. Henry Cuellar and grabbing the Democratic nomination for his sprawling South Texas district.
    
“This is just the beginning,” Cisneros said Wednesday. “The first thing we had to defeat was the culture of fear, and our movement was victorious in proving we're within striking distance of bringing fundamental change to South Texas.”
    
Republicans will need to gain 18 seats on Election Day in their uphill fight to win back control of the House, assuming they retain three seats held by GOP lawmakers who've left office prematurely. The GOP controls the Senate, 53-47.
    
In both chambers, the nature of this November's political battleground spotlights why centrists have been petrified of a Sanders presidential bid.
    
Democrats captured the House majority in 2018 by gaining 42 seats. Of those, 29 are from districts Trump either won in 2016 or lost by a narrow 5 percentage points or less, and most are from districts where moderate suburban voters will be key.
    
In addition, Democrats' hopes of grabbing the Senate majority will hinge on their toppling GOP incumbents in closely divided swing states, including Arizona, Maine, North Carolina and Colorado, where moderate voters are crucial.