Why Super Tuesday could be a key moment in Democratic primaries

Tuesday is the biggest day of the primary calendar, when 14 states from the Atlantic to the Pacific vote on the Democratic presidential nominee.

The US’s two most populous states, California and Texas, and nearly one-third of all the delegates at July’s Democratic National Convention are up for grabs.

Here are some key questions ahead of Super Tuesday:

– Can Bernie Sanders recapture the narrative?

Vermont Senator Bernie Sanders has long promised that he could substantially expand the electorate beyond traditional Democratic voters, but that has not happened in the first four contests.

Super Tuesday represents his biggest chance to prove his case. He is far better financed and organised than former vice president Joe Biden, who trounced Mr Sanders in South Carolina on Saturday.

With five major candidates running, it has been impossible for anyone to claim a clear majority, but Mr Sanders’ durable base has given him a crucial plurality of the vote, and, more important, a small lead in delegates.

Mr 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.

Tuesday represents Mr Sanders’ best chance to build a durable advantage in the race.  And after Tuesday, the terrain shifts to states that are not as favourable to Mr Sanders.

– Can Joe Biden emerge as the “stop Sanders” candidate?

Mr Biden dramatically under-performed in Iowa and New Hampshire, part of a collapse among white voters that allowed Mr Sanders to vault into the lead.

But Mr Biden regained his footing in South Carolina, propelled by the overwhelming support of black voters.

That aided Mr Biden’s case that the candidate who prevails among these base voters will win the nomination.

Mr 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.

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?

Remember 15%. That is the share of votes a candidate has to get to win delegates in primary elections.

With five Democrats left in the race – Elizabeth Warren and Tom Steyer are also competing, while Amy Klobuchar has dropped out – 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 exit of former South Bend, Indiana, Mayor Pete Buttigieg from the race Sunday night, but they certainly did not go away.

That would be a dream scenario for Mr 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?

Former New York Mayor Mike Bloomberg bet more than a half billion dollars on Super Tuesday, and we get to see if it was well spent.

Mr 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 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 Mr Bloomberg’s ultimate impact be to fragment the anti-Sanders vote further and help pave the way for the self-proclaimed democratic socialist whom 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 Mr Sanders.

His campaign has been investing heavily in the state, trying to encourage his supporters to send in early ballots.