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.

9:18 p.m. ABC News projects Biden will win Tennessee's Democratic primary

Based on our analysis of the vote, ABC News projects that Biden will win the Tennessee primary.

9:01 p.m. Sanders outperforming Biden in Colorado, Bloomberg seen as less favorable than opponents

In preliminary results out of Colorado, mainline Democrats -- a core Biden constituency -- make up 63 percent of voters, yet Sanders is running ahead of Biden, 29-20 percent.

On favorability, Warren 72%, Sanders 63% and Biden 63% are broadly popular among voters -- but not Bloomberg, with just 41% favorability.

9 p.m. ABC News projects Trump to win Tennessee

Based on analysis of the vote ABC News projects that Trump will win the Tennessee Republican primary.

9 p.m. Late-deciding voters in Minnesota lean toward Biden

Klobuchar’s exit from the contest Monday and endorsement of Biden distilled the race in Klobuchar’s home state, with liberals and younger adults favoring Sanders, and moderates and late-deciding voters siding with Biden.

Fifty-five percent of voters made their decision in the last few days -- including 22 percent who decided Tuesday, following Klobuchar’s departure from the race Monday. Last-day deciders went heavily for Biden, 41 percent compared with 19 percent for Warren and 18 percent for Sanders. Sanders was stronger among those who decided earlier.

9 p.m. Biden 'feeling optimistic' after Virginia win

At a campaign stop at Rosco's Chicken in Los Angeles, Biden told reporters that "It feels good, I don't know what the outcome, what the actual results are but it feels good and we're feeling optimistic."

Biden wouldn’t comment on what he would consider success tonight, saying he would leave it to the pundits to define it.

A little while later, ABC News asked Biden for his reaction to winning North Carolina, and Virginia—two states he told ABC he felt good about earlier today. When asked if Texas was next, Biden didn’t answer, only crossed his fingers.

ABC News' Molly Nagle reports.

8:48 p.m. Polls closed in Harris County, Texas, but lines still long

When the polls closed in Houston, the Harris County clerk reminded voters they could still cast their ballots if they were in line by 7 p.m. (CST).

And in line they were, according to social media posts.

The Texas Civil Rights Project, lawyers who offered a hotline for anyone to report problems voting, asked that Harris County leaders come together to solve the problem before the general election.

Voters line up at a polling station to cast their ballots during the presidential primary in Houston, Texas on Super Tuesday, March 3, 2020.

Voters line up at a polling station to cast their ballots during the presidential primary in Houston, Texas on Super Tuesday, March 3, 2020.Mark Felix/AFP via Getty Images

"Once again, black and brown voters in #HarrisCo are facing unacceptable wait times in their communities. We know that some voters have already given up and gone home. This is not the first time this has happened. This is a predictable trend in election after election in Harris Co.," the group tweeted.

"We will be following up in the coming weeks with county elected officials as well as county party chairs," the statement continued.

8:46 pm Trump campaign manager takes jab at Bloomberg: 'worst candidate in history'

While Bloomberg spoke to supporters in Florida, Trump's campaign manager attacked his Super Tuesday performance, calling him the "worst candidate in history."

"He might have had great consultants but he might be the worst candidate in history," Brad Parscale, Trump's re-election campaign manager, said in a tweet.

Bloomberg spent more than $234 million in TV, radio and digital advertising ahead of Super Tuesday. He was the only candidate to have ad buys in all 14 states voting tonight.

8:45 p.m. ABC News projects Trump will win Arkansas, Massachusetts Republican primaries

Based on analysis of the vote, ABC News projects that Trump will win the Arkansas Republican primary. And based on analysis of the vote, ABC News projects that Trump will win the Massachusetts Republican primary.

8:45 p.m. Bloomberg is "downplaying expectations" after Super Tuesday showings

Speaking from Bloomberg's rally in Miami, ABC News' Senior White House Correspondent Cecilia Vega said the former mayor is "downplaying expectations."

ABC News’ Chief White House Correspondent Jonathan Karl also said upon hearing Bloomberg’s remarks, “He's certainly not going to be campaigning for Bernie Sanders. He's clearly positioning himself to be very helpful to Joe Biden.”

8:37 p.m. Exit polls show Democrats are moving further left -- even in Texas

According to preliminary exit poll results in Texas, very liberal voters made up 24 percent of the electorate -- a new high, if it holds in later results. Sanders won this group, with 49 percent of voters backing him. Moderates -- also 24 percent of the electorate, down from 34 percent in 2016 -- overwhelmingly backed Biden, with 51 percent. The results reveal how, even in Texas, Democrats are favoring more progressive policies.

8:33 p.m. Biden holds lead in Virginia with 93% of the expected vote reporting

With 93% of the expected vote reporting in Virginia, Joe Biden holds a commanding lead over the rest of the field. Sanders is set for a second place finish behind the former vice president with 23%. Warren and Bloomberg follow with 11 and 10%, respectively.

8:26 p.m. 'Return decency to the White House': GOP figures cast their votes for Biden, Warren

Some prominent Republican figures across the country stepped out for Super Tuesday to vote Democrat.

Among them was John Weaver, a political consultant who worked on John McCain's presidential campaign in 2000 and 2008 and served as the chief strategist for Ohio Gov. John Kasich's GOP run for the White House in 2016.

Weaver announced on Twitter that he had voted for former Vice President Joe Biden in Texas.

ABC News' Ella Torres reports.

8:33 p.m. Bloomberg currently viable in some NC congressional districts>

Bloomberg is currently viable in North Carolina both statewide and in a few congressional districts, with over 30% of expected vote reporting. He's currently above 15% in the 1st, 3rd, 5th and 7th congressional districts.

ABC News' Meg Cunningham reports.

8:22 p.m. ABC News projects Cooper and Forest to face off in North Carolina Governor race

Based on analysis of the vote, ABC News projects that in the race for Governor in North Carolina, Roy Cooper will win the Democratic primary and Dan Forest will win the Republican primary.

8:20 p.m. ABC News projects Tillis to win North Carolina GOP Senate race

Based on analysis of the vote in so far, ABC News projects that Thom Tillis will win the Republican Senate Primary race in North Carolina.

8:11 p.m. ABC News projects Trump to win Vermont and Oklahoma

Based on analysis of the vote, ABC News projects that Trump will win the Vermont and Oklahoma Republican primaries.

8:11 p.m. Biden wins Alabama, Bloomberg wins American Samoa, Gabbard picks up at least 1 delegate in home territory

ABC News has projected that Joe Biden has won the Alabama primary, based on an analysis of the exit polls, and that Michael Bloomberg has won American Samoa's caucus, based on all the precincts reporting. Hawaii Rep. Tulsi Gabbard, who was born in American Samoa, will get her first delegate since voting began, with ABC News estimating she'll get at least one in her home territory.

Voters enter a polling station at the National Guard Military Base during the presidential primary in Camden, Ala., on Super Tuesday, March 3, 2020.

Voters enter a polling station at the National Guard Military Base during the presidential primary in Camden, Ala., on Super Tuesday, March 3, 2020.Joshua Lott/AFP via Getty Images 8:10 p.m. 78% to 87% of Democratic voters say they will support party's nominee

Anywhere from 78% to 87% of Democratic voters in today's primary contests say they’ll back the ultimate nominee no matter who it is, according preliminary exit poll results.

8 p.m. ABC News exit polls reveal trending support for socialism and single payer health care

Among preliminary exit poll results, ABC News detects growing support for socialism and single payer health care among Democratic voters.

In Maine, for instance, socialism is seen favorably by 62% of primary voters.

There's also broad support for a single-payer health care plan in Maine’s preliminary results, 72% -- second highest among states after Vermont -- and Sanders won this group by a wide margin. Health care was seen as the most important issue of four listed among 47 percent of Maine voters, higher than the 40% across the 11 other states with exit poll results Tuesday night.

8 p.m. ABC News projections in Maine and Massachusetts

Based on analysis of the exit polls, ABC News reports Maine is looking like a two-person race between Biden and Sanders.

Massachusetts is looking like a three-person race between Biden, Sanders and Warren.

ABC News also projects that Trump will win the Maine Republican primary.

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.

7:43 p.m. Former Clinton adviser says Sanders has 'unified' Latino voters

Amanda Renteria, the former political director for Hillary Clinton's campaign in 2016, said to ABC News Live Host Linsey Davis that Sanders' success in reaching Latino communities came from talking about "his own immigrant roots."

Sanders has been pushing hard for the Latino vote in states like California and Texas, where they make up a significant part of the electorate. Recent polls indicate Biden has nearly three times the support among Latino Democrats in California as Biden and a 12 percentage-point lead over Biden with Latino Democrats in Texas.

His views on health care and immigration have appealed to Latino voters, something Renteria says has contributed to a feeling of unity.

"Humanity in immigration have unified different Latino communities," she said.

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

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.

7:27 p.m. Trump mocks Bloomberg on Twitter, references coronavirus threat

As Super Tuesday results continue to come in, Trump went after Bloomberg on Twitter with a video of the former mayor licking his fingers while eating pizza at a campaign stop.

The president, a self-described germaphobe, mockingly warned Bloomberg not to lick his “dirty” fingers, seeming to make a joke referencing the growing coronavirus threat.

"Mini Mike, don’t lick your dirty fingers. Both unsanitary and dangerous to others and yourself!" Trump said in the tweet.

Earlier on Tuesday, the president said Super Tuesday will be "an interesting evening of television," but has yet to comment on the contests that have been called -- or on the sole contest Bloomberg has been projected to have won so far, American Samoa.

ABC News' Will Steakin reports.

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.

7 p.m. ABC News preliminary exit poll: Virginia Democrats say Biden is best to beat Trump

According to an ABC News exit poll among Democrats who voted in Virginia Tuesday, former Vice President Joe Biden benefits from his personal popularity, a sense that he can beat Trump, and his strength among the black electorate in Virginia, while Sen. Bernie Sanders, I-Vt. is strong among very liberal and younger voters. Moderates and older voters keep former New York City Mayor Michael Bloomberg in the hunt, while more educated voters -- and especially college-educated women – are a stronger group for Sen. Elizabeth Warren, D-Mass.

Asked who they think is best able to beat Trump in November, 53% of voters picked Biden; 21%, Sanders; 12%, Bloomberg; and 7%, Warren.

7 p.m. ABC News preliminary exit poll: Vermont Democrats favor single government healthcare plan, want a candidate who can beat Trump over one who agrees on issues

According to a preliminary ABC News exit poll among Democrats who voted Tuesday in Vermont, Sanders dominated among young adults, independents and liberal voters alike in his home state. He also won handily among voters who want to see a single-payer health care plan, crowding out support for Warren in predominantly liberal Vermont.

Seventy-five percent in Vermont were in favor of replacing all private health insurance with a single government plan, the most in states with exit polls today or in any previous stated -- a signature issue for Sanders and Warren alike.

Sixty-two percent would rather see the Democratic Party nominate a candidate who can beat Donald Trump versus 35 percent for one who agrees with them on major issues. Among those who cared more about electability, 46 percent cast their vote for Sanders while 29 percent went for Biden.

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%.

Voters enter a polling station at the National Guard Military Base during the presidential primary in Camden, Ala., on Super Tuesday, March 3, 2020.

Voters enter a polling station at the National Guard Military Base during the presidential primary in Camden, Ala., on Super Tuesday, March 3, 2020.Joshua Lott/AFP via Getty Images5:13 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?