Whether or not Joe Biden's much-needed victory in the South Carolina presidential primary only temporarily slowed Bernie Sanders' momentum, it did rekindle talk about the prospects of a brokered Democratic National Convention in July.

Biden, Barack Obama's former vice-president, won't get long to savor Saturday's victory, his first ever as a US presidential candidate.

That is because on Tuesday, or Super Tuesday as it's known, 14 states will weigh in on the Democratic field, with 34 percent of pledged delegates at stake.

Four leading candidates will be vying for chunks of the delegate pie after three other contenders dropped out just since Saturday.

Besides Sanders and Biden, the two other main contenders are billionaire former New York City mayor Michael Bloomberg and US Senator Elizabeth Warren of Massachusetts. US Congresswoman Tulsi Gabbard of Hawaii is still running but has not won any delegates so far.

US Senator Amy Klobuchar of Minnesota announced on Monday that she was halting her campaign and said she would support Biden.

Pete Buttigieg, former mayor of South Bend, Indiana, surprised the political establishment Sunday when he announced he was wrapping up his run.

Both Klobuchar and Buttigieg headed to Texas to appear with Biden at a rally on Monday evening in Dallas.

US President Donald Trump said on Twitter on Sunday that Buttigieg's leaving the race was part of an effort to deny Sanders the nomination.

"Pete Buttigieg is OUT. All of his SuperTuesday votes will go to Sleepy Joe Biden. Great timing. This is the REAL beginning of the Dems taking Bernie out of play - NO NOMINATION, AGAIN!

After Trump tweeted on Monday that "They are staging a coup against Bernie!", the senator, appearing on CNN, said: "President Trump, stay out of the Democratic primary."

Billionaire environmentalist Tom Steyer dropped out of contention Saturday.

Biden handily won the South Carolina primary with 48 percent of the vote, bolstered by the endorsement of US Congressman Jim Clyburn, who has wide influence with the state's African American voters.

"My buddy Jim Clyburn, you brought me back!" Biden, 77, exclaimed at his victory celebration on Saturday.

There is another endorsement Biden has coveted, that of Obama's, who has said he won't be making one any time soon.

Sanders, 78, a US senator from Vermont, was looking ahead to California after Saturday's second-place finish.

"There are a lot of states in this country," he told supporters. "Nobody wins them all."

With fewer candidates in the mix, it appears less likely the nomination will be decided at the convention, unless Biden, Bloomberg and Warren can find a way to proportionally siphon delegates from Sanders.

In Democratic presidential primaries, only candidates who win 15 percent of the vote are awarded any pledged delegates.

California and Texas are the delegate-rich prizes on Tuesday, where Sanders is leading in polls in both states. Voters in Warren's home state of Massachusetts and in Sanders' Vermont also will go to the polls Tuesday.

A CBS News Battleground Tracker/YouGov poll released Sunday shows Sanders with a sizable lead in the Golden State, with 31 percent, followed by Biden at 19 percent, Warren at 18 percent and Bloomberg at 12 percent. In California, there are 415 pledged delegates at stake, the most of any state.

A handful of recent polls in Texas, with 228 pledged delegates up for grabs, show Sanders leading Biden but also have Bloomberg in double digits.

The other states holding primaries Tuesday are: Alabama, Arkansas, Colorado, Maine, North Carolina, Oklahoma, Tennessee, Utah and Virginia. The territory of American Samoa also will vote Tuesday, as will Americans who are Democrats living outside the US.

Tuesday also will be Bloomberg's first appearance before primary voters. The 78-year-old financial news company founder entered the race late and wasn't on the ballot for the four previous contests: the South Carolina and New Hampshire primaries and the Iowa and Nevada caucuses.

How Bloomberg fares Tuesday should go a long way toward determining how long he will continue to spend millions of dollars on political advertising around the country.

Bloomberg ran a three-minute prime-time ad both on CBS and NBC on Sunday, to tout his credentials as a crisis manager as he criticized Trump's response to the coronavirus.

"The coronavirus is spreading, and the economy is taking a hit," Bloomberg said in the commercial, which featured a presidential-looking backdrop. "Markets have fallen because of uncertainty. At times like this, it's the job of the president to reassure the public that he or she is taking all of the necessary steps to protect the health and well-being of every citizen."

As for Warren, who so far has secured only eight delegates (from the Iowa caucuses), a campaign memo released Sunday said that she is banking on a good showing Tuesday.

"We expect Elizabeth to have a strong delegate performance on Super Tuesday, and see the race narrowing considerably once all the votes are counted," wrote campaign manager Roger Lau.

Lau said that Warren's campaign raised more than $29 million in February, and he expects the race to be unsettled before the convention.

"But as the dust settles after March 3, the reality of this race will be clear: no candidate will likely have a path to the majority of delegates needed to win an outright claim to the Democratic nomination."

Sanders so far has tallied 60 delegates, followed by Biden with 54. Buttigieg collected 26 before withdrawing.

A lot has been made of the influence of the Democrats' 771 superdelegates, also called automatic delegates, who are current and former members of Congress, former presidents and governors, members of the Democratic National Committee and other party luminaries.

They, however, do not get to vote on the first ballot at the convention, when the pledged delegates from each state do. Those 3,979 pledged delegates are generally expected to vote for the candidate whom their state's voters selected.

After the delegates from the states are counted, if no single candidate has the 1,991 required, then the 771 superdelegates can vote on the second ballot. Those superdelegates can vote for any candidate they choose, which can lead to what is known as a "floor fight" for the nomination.

The number of delegates needed to secure the nomination on the second ballot is 2,376.

Sanders has said that whichever candidate has the most delegates headed into the convention (July 13-16) in Milwaukee, Wisconsin, should get the nomination, even if that candidate is shy of the total needed to clinch it.

But many in the party's hierarchy have expressed opposition to Sanders and his democratic socialist platform, which includes free healthcare and college tuition, worried that such an ideology would not fare well against Trump in the general election in November.

"The establishment is nervous, not because we can't beat Trump, but because we will," said Sanders' campaign manager, Faiz Shakir, according to Reuters. "And when we do, the Democratic Party will again be a party of the working class."

Sanders has pointed to polls that show him beating Trump, and Senate Majority Leader Mitch McConnell, a Republican from Kentucky, has said it would be foolhardy for Republicans to assume Sanders would be an easy opponent.