Race for the White House: What is Super Tuesday and why is it important?

Joe Biden's campaign has fresh momentum after the former Vice-President's win yesterday in South Carolina. Photos / AP

There is no national primary for US presidential nominations, but Super Tuesday is as close as it gets.

This week we will see the most states hold nominating contests, the most voters have a chance to go to the polls, and the most delegates will be allotted to candidates. More than a third of all delegates for the Democratic National Convention are up for grabs.

What happens on Super Tuesday - which is on Wednesday NZT - will shed some light on the big questions around the Democratic presidential primary - and there are a lot more questions than usual at this point in an election cycle.

Here's what you should know.

THE STATES:

Fourteen states and one US territory will hold contests for 1357 delegates.

The states are across the country - literally from California to Maine - and include heavily Democratic Massachusetts, traditionally Republican Texas and Oklahoma and more in-between states such as Colorado, North Carolina and Virginia. Democrats who live in American Samoa will also caucus.

It's the delegate total, not the sheer number of votes, that counts when figuring out who wins a party's presidential nomination. Each state is allotted a certain number of delegates based on a formula of population and weight in the Democratic Party. The state parties then award delegates to the candidates based on the votes they receive. The first candidate to get a majority of the nearly 4000 delegates wins the nomination.

This year, Super Tuesday is even more consequential because California moved its primary up to March 4. It had been voting in June, at the tail end of the nominating process when there's typically less at stake. The addition of the most populous state adds even more heft to Super Tuesday; 30 per cent of the delegates awarded will come from California.

THE STAKES:

No one can win the nomination on Wednesday alone, but doing well can get you a long way towards winning a majority of the 3979 delegates up for grabs. Thirty-four per cent of delegates are offered. That's more than any other single day.

Before Super Tuesday, less than 5 per cent of delegates will have been allotted. After: 38 per cent.

THE RACE:

Heading into Super Tuesday, the race for the Democratic nomination still lacks clarity.

After winning convincingly in Nevada, Senator Bernie Sanders of Vermont has taken the lead on delegates and leads in recent national polling.

Former South Bend, Indiana, mayor Pete Buttigieg won Iowa and finished second in New Hampshire.

Former Vice-President Joe Biden won yesterday's South Carolina primary, putting him back in contention.

But there is still a long way to go to decide the nomination. And no nominating contest has presented a potential shake-up like the one this Super Tuesday could provide. With the race still in flux and 14 states voting all at once, Super Tuesday could serve as a gut check for where the Democratic Party electorate is.

There is another reason Super Tuesday could have an especially big impact this year: Former New York mayor Mike Bloomberg will first appear on ballots.

He entered the race late, skipped the early states and has spent some US$350 million of his own money on campaign ads, and his standing in the polls, including among black voters, has risen.

Senator Bernie Sanders has been leading polls in most of the Super Tuesday states.

THE STRATEGIES:

Super Tuesday states have 10 times the population of earlier-voting states

Nearly 130 million people live in the 14 states with primaries on Super Tuesday - more than 10 times as many people who live in the four states with caucuses and primaries before Super Tuesday.

Their strategies, much like the elections themselves, are all over the map. Sanders is making a big play for California. Polls there suggest it's possible that only he reaches the 15 per cent of support that the Democratic Party requires candidates reach in order to win statewide delegates. (Other candidates can win delegates that individual congressional districts hand out.)

If Sanders manages to eliminate most of his competition in California, it would be a huge boost for his campaign. But remember, we won't know the full results in California until well after the primary, so it's hard to discern what that big delegate payout will do for the momentum of the race.

The candidates are also focused on Texas and a thriving Democratic Party there.

Sanders, Senator Elizabeth Warren, Buttigieg and Biden all plan to travel there or have already travelled there recently. Polls show Sanders competetive in Texas with Biden. A CNN poll released on Saturday found Sanders with a big lead in both California and Texas.

Warren and Senator Amy Klobuchar are both hoping to win their home states (not doing so doesn't bode well).

And Bloomberg has been advertising heavily in Super Tuesday states for months now, specifically tailoring his message to appeal to black voters in states like North Carolina. A poll in the state released on Saturday shows him bunched up with Sanders and Biden.

Former mayor Peter Buttigieg met former President Jimmy Carter at the Buffalo Cafe in Plains, Georgia.

WHAT TO WATCH FOR:

A few things. Like:

1) How does Bloomberg do on the ballot? It's the first time he'll be on, due to his novel strategy of skipping the early states. He has momentum, from what we can tell from early state polls. But that rise is coming with increased scrutiny of his racially divisive policies as mayor and history of crude comments to women and gender-discrimination lawsuits at the company he runs. His first time on the debate stage recently, he struggled to defend his past.

2) Does Warren survive beyond Super Tuesday? She has finished below the top two in all four early nominating contests. Warren's campaign has looked to Super Tuesday states for wins to bring her back in the game. But what happens if she doesn't win much of significance? Same with Klobuchar, who has performed poorly with voters of colour since her third-place finish in New Hampshire, and Buttigieg, who hasn't won a contest since Iowa.

3) Does Super Tuesday blunt Sanders's momentum in any way? Since the Iowa caucuses, Sanders has been leading in national polls. But some polls in Super Tuesday states show he is bunched up with other candidates, such as Biden and Warren and Bloomberg. Sanders still has plenty of convincing to do within the Democratic establishment that he can beat Trump, and finishing outside the top three in a significant number of Super Tuesday states could seriously ding his argument that he can win a national election.