The race for the Democratic Party presidential nomination has reached arguably it’s most significant moment: Super Tuesday.

It represents elections in 14 US states, as well as an overseas territory and Democrats who live outside the country, where the candidate to go head-to-head with Donald Trump in November could emerge.

What happens on Super Tuesday?

The magic number to win the Democratic Party’s nomination for president is 1,991 delegates, with each state having a set number of delegates to award candidates.

About 1,357 delegates, or nearly one-third of the total number, are up for grabs on Super Tuesday, making it the biggest day of the state-by-state contests that mark primary season. The US’s two most populous states, California and Texas, are among those going to the polls.

The delegates will vote for the selected candidate at July’s Democratic National Convention, when the nominee is officially selected. But it could get messy if no candidate has a majority by then.

Who is running for president against Trump?

The field of candidates at this stage was set to be the largest in recent memory, but has been whittled down after Pete Buttigieg and Amy Klobuchar dropped out in the last two days as so-called moderates tried to coalesce their support around Joe Biden, the former vice president who enjoyed a resounding victory in Saturday’s South Carolina primary.

They appear to be attempting a takedown of Bernie Sanders, the independent ‘democratic socialist’ from Vermont and frontrunner who has shaken the Democratic establishment with his grassroots-powered campaign.

Billionaire former New York Mayor Mike Bloomberg makes his first appearance on primary ballots in Super Tuesday states, where he has bet hundreds of millions of dollars of his own money to boost his campaign. Biden’s resurgence could stunt his efforts, however.

Senator Elizabeth Warren, who has fallen well behind Sanders as the left-wing candidate of choice, remains in the race, as does the Hawaii congresswoman Tulsi Gabbard, despite polling well behind the recent drop-outs.

A state-by-state breakdown

The biggest prize: California (415 delegates)

The second biggest prize: Texas (228)

The South: Alabama (52), Arkansas (31), North Carolina (110), Tennessee (64)

The Newly Democrat states: Colorado (67), Virginia (99)

The home turf for candidates: Maine (24), Massachusetts (91), Minnesota (75), Oklahoma (37), Vermont (16)

The surprisingly liberal state: Utah (29)

The wild cards: American Samoa (6), Democrats Abroad (13)

Can Bernie Sanders regain momentum?

Sanders, who says he seeks nothing less than a political revolution, won New Hampshire and Nevada, finished a close second in Iowa to Buttigieg and well behind Biden in South Carolina.

With his signature promise of government-run universal healthcare, Sanders has again proven to be a fundraising powerhouse, leading the field in total campaign contributions.

Super Tuesday represents Sanders’ biggest chance to prove he can substantially expand the electorate beyond traditional Democratic voters, and are vital as after Tuesday the terrain shifts to states that are not as favourable to him.

Sanders needs as many delegates as possible because his opponents argue the convention itself should decide the nominee should no one secure a clear majority.

Are moderates rallying around Joe Biden?

Biden dramatically under-performed in Iowa and New Hampshire, part of a collapse among white voters that allowed Sanders to vault into the lead. But he regained his footing in South Carolina, propelled by the overwhelming support of black voters.

Biden’s campaign hopes that allows him to vastly overperform his polls for Super Tuesday and consolidate the splintered anti-Sanders factions in the Democratic Party, with the supporters of Buttigieg and Klobuchar most likely to break to him.

The hope in the former vice president’s camp is that it becomes effectively a two-person race after Tuesday, which may give him an advantage in upcoming states like Florida, Illinois and Pennsylvania.

Which candidates can stay viable?

Another key figure is 15%. That is the share of votes a candidate has to get or they won’t be eligible to receive delegates in most places.

With five Democrats left in the race, there is a real threat that only one or two will actually grab delegates, with the rest splitting the remaining vote in the low teens.

The risks of that diminished with the exits of Buttigieg and Klobuchar, but they did not go away.

That would be a dream scenario for Sanders, who in some states could grab a far greater proportion of available delegates than his vote share would represent.

Some polls have shown it as a distinct possibility in delegate-rich California.

Does Michael Bloomberg’s big bet pay off?

Bloomberg is a billionaire, and rather than competing in the first four primary states, he decided to spend a huge sum of money on advertisements and campaign organisations in the 14 states voting on Tuesday, as well as on other ones voting in the coming weeks.

But since he first appeared on the debate stage, his polls plummeted and now he runs the risk of falling into the sub-15% zone in a number of states.

Even if he does not, will Bloomberg’s ultimate impact be to fragment the anti-Sanders vote further and help pave the way for the politician he says he got in the race to stop?

How does the California count affect the race?

California is different. It is the biggest prize on the board Tuesday with more than 400 delegates at stake.

But California has an unusual voting system that counts all ballots cast Tuesday, even if they were only put in a mailbox that day. It can take weeks to count the entire vote.

That could help or hurt Sanders. His campaign has been investing heavily in the state, trying to encourage his supporters to send in early ballots.