As Super Tuesday, the single biggest day of voting gets underway, the candidates are competing across 15 contests for a treasure chest of delegates, which will be awarded across geographically and racially diverse parts of the country.

The stakes could not be higher as Democrats face a significant turning point in the 2020 presidential race and are tested on a national scale.

Across 14 states -- Alabama, Arkansas, California, Colorado, Maine, Massachusetts, Minnesota, North Carolina, Oklahoma, Utah, Tennessee, Texas, Vermont and Virginia -- and one territory, American Samoa, 1,344 delegates are up for grabs.

Here's how the day is unfolding. Please refresh for updates.

7:51 p.m. Bloomberg the only Democratic candidate who spent on digital ads in American Samoa

Michael Bloomberg spent a modest $904 running online ads in American Samoa. Bloomberg is the only candidate in the 2020 Democratic primary field to spend on digital ads in American Samoa.

It's unclear if he spent any money on television or radio ads in American Samoa because they're not reported the same way as other markets.

ABC News' Soorin Kim reports.

7:34 p.m. ABC News projects Bloomberg to win American Samoan

Based on 100% of precincts reporting, ABC News can say that Bloomberg has won the American Samoan caucus.

7:32 p.m. Warren speaks to supporters in Detroit

Speaking to supporters in Detroit, Warren told supporters, "I'm in this race because I believe I will make the best president of the United States of America."

The senator began the day campaigning in her home state of Massachusetts before traveling west to Michigan.

Reporting from the Michigan rally, ABC News Senior National Correspondent Terry Moran says of the Warren campaign, "It doesn't look like they're going to get a victory anywhere" and that they're hoping for a deadlock convention.

"There's tremendous emotion, tremendous affection for this candidate," Moran said. "She connects with people, just not enough."

Sen. Elizabeth Warren poses for a photo ahead of her Super Tuesday night event on March 03, 2020, in Detroit.

Sen. Elizabeth Warren poses for a photo ahead of her Super Tuesday night event on March 03, 2020, in Detroit.Scott Olson/Getty Images 7:30 p.m. ABC News projects Biden to win North Carolina

Based on analysis of the exit poll, ABC News projects that Biden will win the North Carolina Democratic primary and Trump will win the Republican primary.

"I Voted" stickers cover a table at a polling station during the North Carolina primary on Super Tuesday in Charlotte, N.C. on March 3, 2020.

"I Voted" stickers cover a table at a polling station during the North Carolina primary on Super Tuesday in Charlotte, N.C. on March 3, 2020.Logan Cyrus/AFP via Getty Images 7:30 p.m. ABC News preliminary exit poll: North Carolina Democrats boost Biden, say he's best to beat Trump

A focus on electability and broad support from black voters boosts Biden in North Carolina, while 18- to 29-year-olds and those who support a shift to more liberal policies than Barack Obama's back Sanders, according to a preliminary ABC News exit poll. Bloomberg is the wildcard, albeit with voter concerns about vast campaign spending from candidates' personal pockets.

7:06 p.m. Biden says it's 'possible' he wins Texas tonight

Speaking to reporters at an ice cream shop in Los Angeles, Joe Biden told ABC News that he thought it was "possible" he could win Texas, the second largest prize.

Democratic presidential candidate and former Vice President Joe Biden gets ice-cream at La Michoacana during the state's Democratic presidential primary election on Super Tuesday in Los Angeles, March 3, 2020.

While the former vice president said he did not want to speculate about his chances, he said, "I feel very good about particularly Texas, Virginia, North Carolina -- I even feel good about California, but we in got late in the game. And so we'll see, we'll see."

ABC News' Molly Nagle reports.

7:02 p.m. Sanders campaign says 'political establishment' has chosen Biden as their candidate

In a fundraising email sent Tuesday evening, the Sanders campaign responded directly to the developments in the presidential race over the past few days.

"The political establishment has chosen their candidate," the email read. "It's Joe Biden. And they're lining up behind him in an effort to derail our momentum in this race."

Although Sanders attacked Biden at a rally in Minnesota Monday night, he did not directly reference the former vice president's recent endorsements from former Mayor Pete Buttigieg, Sen. Amy Klobuchar and former Rep. Beto O'Rourke.

The campaign said it will need "an incredible amount of resources" to win the states following Super Tuesday.

"We need a lot of donations to stay on track to win," the campaign said in the email. "Because after tonight's results, we expect super PAC spending will increase dramatically in order to defeat us."

ABC News' Adam Kelsey reports.

7 p.m. ABC News projects Sanders to win Vermont, Biden to win Virginia

Based on analysis of the exit poll, ABC News projects that Sanders will win the Vermont and Biden will win the Virginia primaries.

6:48 pm Bloomberg campaign manager: Bloomberg "absolutely" won't drop out tonight

Former New York Mayor Mike Bloomberg's campaign manager Kevin Sheekey suggests they are laying the groundwork for an off-ramp for their candidate.

"I think Mike Bloomberg is either the candidate for the party or the single most important person helping that candidate defeat Donald Trump," he said.

Asked it there is a a chance mayor Bloomberg drops out tonight, Sheekey responded: "Absolutely not. Anyone that's expecting an early night, anyone whose expecting the kind of night where they can go home and go to sleep early can forget about it."

Democratic presidential candidate Michael Bloomberg speaks during a press conference at his campaign office in Little Havana, Miami, March 3, 2020.

Democratic presidential candidate Michael Bloomberg speaks during a press conference at his campaign office in Little Havana, Miami, March 3, 2020.Marco Bello/Reuters 6:05 p.m. Judge rules Nashville polls must remain open until 8 p.m. (CST) at all Davidson County locations. Five sites to remain open until 10 p.m.

A Davidson County Judge Tuesday afternoon ruled that polls can remain open until 8 p.m. (CST) at all sites across Nashville, in the wake of a deadly tornado. Polls were originally set to close at 7 p.m. The following five polling sites will remain open until 10 p.m.:

Election Commission Office, 1417 Murfreesboro Pike. Howard Office Building, 700 Second Ave. S. Cleveland Community Center, 610 Vernon Winfrey Ave. Donelson Presbyterian Church, 2305 Lebanon Pike. Pearl Cohn High School, 904 26th Ave. N.

The ruling came at the request of four of the top Democratic presidential campaigns, along with the Tennessee Democratic Party, the Nashville Tennessean reports. The groups filed suit in a Nashville court on Tuesday to extend poll times amid heavy tornado damage throughout the city.

ABC News' Kendall Karson reports.

6 p.m. Democratic presidential candidates blast Trump administration on coronavirus response

Meanwhile, even amid Super Tuesday voting, the health threat and economic repercussions of coronavirus loom large. Democratic presidential candidates are unanimously condemning the Trump administration's handling of the outbreak. In turn, President Donald Trump has accused the Democrats of "politicizing" the issue, characterizing it as "their new hoax."

Although every Democratic presidential contender has attacked the administration for its response, only two candidates, Sen. Elizabeth Warren , D-Mass., and former New York City Mayor Michael Bloomberg, have offered formal plans to combat health crises, including COVID-19.

ABC News' Arielle Mitropoulos reports here.

In turn, President Donald Trump has accused the Democrats of "politicizing" the issue, characterizing it as "their new hoax."

90,000 cases of coronavirus worldwide. The U.S. has confirmed at least 108 cases of the virus, including several "community-acquired" cases in which the individuals had no known exposure to the COVID-19 virus through travel or close contact with an infected individual.

5:38 p.m. Democratic Party spokeswoman: Judge has ruled all Tennessee polls must extend hours in wake of tornado

In the wake of a deadly tornado which killed at least 25 people, a judge has ruled all Tennessee polls must extend Super Tuesday hours. Voters in Tennessee were rerouted to other polling stations after deadly tornadoes ripped through the state.

5:25 p.m. Voters in several states weigh in on having a self-proclaimed Democratic-Socialist on the ballot

There's a "democratic socialist" on the ballot, Sanders, and exit polls in five states asked voters if they have a favorable or unfavorable opinion of socialism. Answers varied, from a high of 62% favorable in Maine to a low of 47%in Tennessee, given currently available results.

According to ABC News reporting, 57% of Democratic voters in preliminary exit poll results from Texas have a favorable opinion of socialism.

Texans come in ahead of North Carolina and Tennessee, behind Maine, in receptivity to socialism.

Sanders has been targeted for his Democratic socialist views -- which include tuition-free college and Medicare for all. He has made the argument that democratic socialism is "less radical than characterized by opponents," and also says it's the easiest way to differentiate his campaign from Trump.

Democratic presidential candidate Sen. Bernie Sanders cast his vote with his wife Jane O'Meara Sanders at a polling place March 3, 2020 at Robert Miller Community Center in Burlington, Vt.

Democratic presidential candidate Sen. Bernie Sanders cast his vote with his wife Jane O'Meara Sanders at a polling place March 3, 2020 at Robert Miller Community Center in Burlington, Vt.Alex Wong/Getty Images

ABC News Chief Anchor George Stephanopoulos questioned Biden on whether or not he believes a Democratic candidate with socialist beliefs could defeat Trump in early February.

"I think it's going to be incredibly more difficult," Biden said in the exclusive interview.

5:15 p.m. How much could late-breaking events sway results

With early voting going on for a good while in most states, the potential influence of late-breaking events is an open question – particularly, former Vice President Joe Biden's win in South Carolina and former South Bend, Indiana Mayor Pete Buttigieg's and Minnesota Sen. Amy Klobuchar's decisions to withdraw from the race and endorse Biden. In preliminary exit poll results, anywhere from 31% in Tennessee to 47% in Oklahoma and Virginia alike said they finally made up their minds just today or in the last few days.

5:13 p.m. Anger at Trump unites Democrats

While divided in their vote preferences for the party's nominee, Democratic voters are united in dissatisfaction – and for some, even anger – with the Trump administration. Anywhere from 83 to 94% in preliminary results say they're either angry or dissatisfied with the current administration. Anger peaks in Maine 79%, Colorado 77% and Vermont 75%.

5:13 p.m. Racial and ethnic groups are worth watching at the state level

Racial and ethnic groups are worth watching at the state level, ABC News' Director of Polling Gary Langer points out. Turnout among blacks should be important given their vast support for Biden in South Carolina, where they accounted for 56 percent of primary voters and backed Biden over Sanders by 61-17%. Preliminary results tonight find black turnout highest in Alabama 44%, North Carolina 27%, Virginia 27% and Tennessee 26%.

Hispanics accounted for just 5 percent of voters in the early states overall, rising to 17 percent in Nevada. They're expected to account for many more voters in two states – Texas 32% in 2016 and California 30% in 2008, the last year for which we have exit poll data. We'll update with tonight's figures as those data come in.

Before today, Hispanics voted for Sanders over Biden by 41-20% overall, and by 50-17% in Nevada, where they were particularly young, 55% younger than 45 and supportive of single-payer government health care, two strong Sanders groups.

5:12 p.m. Here's some math to ponder

As ABC News Deputy Political Director MaryAlice Parks writes: "On Tuesday night alone, more than 30% of all of the Democratic Party's pledged delegates are up for grabs in some of the largest states in the union: California has 415 delegates, Texas has 228. Virginia and North Carolina are also voting, both of which have double the number of delegates compared to South Carolina. When the dust settles from the Super Tuesday states, 1499 delegates will have been awarded."

With so much of the delegate pool at stake in one night, will a single candidate walk away with a lead in delegates that is hard to catch or will the math shake out to show a great divide that could take months to heal and process?