The Democratic presidential candidates are in crunch mode as they prepare for the most important day in the primary race so far: Super Tuesday.
More than a million voters across over a dozen states have already voted early or by mail-in ballot, but the rest will head to the polls Tuesday to make their choice.
Here’s what you need to know:
When is Super Tuesday?
Tuesday, March 3. Poll closing times depend on the state, with Vermont and Virginia first at 7 p.m. ET and California last at 11 p.m. ET.
Which states participate?
14 states in total: Alabama, Arkansas, California, Colorado, Maine, Massachusetts, Minnesota, North Carolina, Oklahoma, Tennessee, Texas, Utah, Virginia, and Vermont. American Samoa also holds its Democratic caucuses. The Democrats Abroad primary also begins Tuesday (and runs through the following Tuesday.)
When will we know the results?
For most of the states in play, we'll get results in the hours after polls close. The one exception is California, which is notoriously slow to count its ballots. It accepts mail-in ballots up to three days after election day and gives county election officials 30 days to count them. In 2016, it took over a month to count them all its ballots.
How many Democratic delegates are at stake?
There will be more than 1,300 delegates allocated on Super Tuesday, about a third of the total delegates and the most up for grabs on any single day in the primary calendar.
When you add in the 155 delegates from the four early voting states — Iowa, New Hampshire, Nevada and South Carolina — nearly 40 percent of the total delegates will have been awarded after Super Tuesday.
A candidate needs 1,991 delegates to secure the nomination.
How are delegates allocated?
There are two types of delegates that can be awarded: statewide (or at-large) delegates and district-level delegates.
Candidates must receive at least 15 percent of the vote statewide in order to receive any statewide delegates and must also meet the 15 percent threshold in a congressional district in order to receive any district-level delegates. Those who fail to meet 15 percent will be locked out.
With so many candidates still in the race and no clear front-runner, there are a wide range of possible outcomes on Super Tuesday.
We could see multiple candidates reach 15 percent and pick up delegates, potentially prolonging the primary and making the possibility of a contested convention more likely.
Alternatively, if bottom-tier candidates struggle to reach 15 percent, then we could see a significant separation in the delegate lead.
Why does it matter?
The sheer number of delegates up for grabs makes Super Tuesday the most pivotal day on the primary calendar. While no candidate can win the nomination outright Tuesday, someone could pull far ahead and out of striking distance in the delegate count.
Super Tuesday is also a chance for candidates to show whether they are able to put together a diverse coalition. This is especially true for California and Texas — the states with the most amount of delegates. In California, for example, roughly 30 percent of eligible voters are Hispanic and 14 percent are Asian.
We might see the field winnow after Super Tuesday, too. Candidates who performed poorly in the early states were able to argue that only a tiny percentage of delegates had been allocated, and that the race was far from over. That argument will be much harder to make for those who fail to have a strong showing Tuesday.
What to keep an eye on this Super Tuesday?
Sen. Bernie Sanders, I-Vt., will look to sweep delegate-rich states such as California and Texas with large Latino populations to assure his path to the nomination, while former Vice President Joe Biden, fresh off a big win in South Carolina, will focus on proving he has strong support nationwide, too.
Candidates like Sen. Elizabeth Warren, D-Mass., who have struggled to perform well in early states, will be looking to pick up just enough delegates to keep their campaigns afloat.
Three candidates — Minnesota Sen. Amy Klobuchar, Warren and Sanders — will be keeping an eye on how their home states vote. A home state loss could be a serious setback, especially for Klobuchar and Warren.
One wild card to watch out for this year: Tuesday will be the first time former New York City Mayor Mike Bloomberg will appear on a ballot. Bloomberg, who entered the race late, skipped early voting states entirely, instead focusing his efforts on Super Tuesday. Bloomberg has banked his entire candidacy on Super Tuesday, and we will soon see just how effective his unconventional strategy is.
How did Super Tuesday come to be?
The term "Super Tuesday" was used as early as the 1976 primary to refer to the California, Ohio and New Jersey nominating contests held in June.
But Super Tuesday as we know it today did not come to be until 1988. Southern Democratic governors, frustrated by the 1984 election when Walter Mondale lost every single state but one to President Ronald Reagan, sought to have a bigger say in the party’s nomination earlier on in the calendar. If the South could have more influence in the primary, they reasoned, they could help pick a candidate better suited to win the general election.
Southern states agreed to move up their primary and on March 8, 1988, 20 states and one territory voted in the presidential primary.
Although Super Tuesday still includes mostly Southern states today, it has expanded to include other states such as California and Vermont.