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March 17 Democratic primaries live updates: Biden sweeps Sanders as coronavirus casts shadow over vote

Tuesday's primaries were the first since Trump declared a national emergency over the coronavirus outbreak.

Joe Biden defeated Bernie Sanders in Florida, Illinois and Arizona, NBC News projected Tuesday, opening up a nearly insurmountable delegate lead.

In Ohio, polls were ordered closed as a public health measure after a judge declined the governor's request to postpone the election. But contests in the other three states proceeded as scheduled Tuesday despite widespread fears over the rapidly spreading coronavirus pandemic.

The outbreak, which has sickened more than 5,000 people in the U.S., is thrusting the Democratic primary into uncertainty, with some states postponing their elections and the candidates forgoing rallies for virtual events.

Highlights from the March 17 Democratic primaries:

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Biden wins Arizona primary to cap three-state sweep, NBC News projects

Biden wins the Arizona Democratic primary, NBC News projects, capping a sweep of contests in three states on Tuesday.

The trio of wins allowed the former vice president to grow his lead in the total delegate count over Sanders and tighten his grip on the Democratic presidential nomination.

With 62 percent of the vote in Arizona in, Biden led Sanders 44 percent to 31 percent.

There are 67 pledged delegates at stake in Arizona. As of 11:15 p.m. ET, Biden had received 23, while Sanders was awarded 19, according to NBC News.

Earlier in the night, Biden defeated Sanders in the Florida and Illinois Democratic primaries, according to NBC News projections, allowing Biden to open up what could be an insurmountable delegate lead in the battle for the nomination.

As of of 11:15 p.m ET, an NBC News projection of the total delegate count showed Biden leading Sanders 1,124 to 815. 

To win the nomination on the first ballot, a Democratic candidate must receive support from a majority of pledged delegates — at least 1,991.

Key takeaways from Florida, Illinois: Biden cruising to the nomination

WASHINGTON — Joe Biden won dominant victories in Florida and Illinois on Tuesday as he marched closer to the Democratic presidential nomination amid coronavirus mayhem.

The former vice president was on course to expand his lead and cross the halfway mark toward the 1,991 delegates needed to clinch the nomination on the first ballot.

The primaries came as the coronavirus outbreak wreaked havoc on American life and sent the economy into a tailspin, though large numbers of votes had already been banked in the early voting period. Arizona polls were set to close later. Ohio postponed its primary at the last minute.

Below are some key takeaways from Florida and Illinois.

WATCH: Kornacki breaks down Biden's victory in Illinois

Biden appeals to Sanders supporters, discusses pandemic in somber victory speech

Biden, in a solemn online address to supporters, quietly welcomed his primary wins in Florida and Illinois by praising Sanders and explicitly reaching out to the Vermont senator's youthful supporters.

“To the young voters” who have gravitated toward Sanders, Biden said, “I hear you, I know what’s at stake.”

“Senator Sanders and I may disagree on tactics, but we share a common vision,” Biden said, before listing off several policy priorities he said he shared with Sanders, including “affordable health care” and “tackling the existential challenge of climate change.”

In brief remarks that largely focused on the national response to the coronavirus pandemic, Biden said it was “important for us to get through this crisis protecting both the public’s health and our democracy.”

“Tackling this national epidemic is a national emergency akin to fighting a war,” he said. 

Biden thanked poll workers and public health experts for allowing the polls to remain open in Illinois, Florida and Arizona, and said that, “today it looks like once again …  our campaign has had a very good night.”

Biden made his address from his hometown of Wilmington, Delaware. Supporters and reporters were able to watch the remarks via live stream. Biden, like Sanders, has in recent days made all campaign events “virtual events” to help slow the spread of coronavirus.

NBC News Primary Poll: Arizona's Latino voters split between Biden and Sanders

Latino voters made up 27 percent of the electorate in Tuesday's Arizona Democratic primary, and they were split between Joe Biden and Bernie Sanders, according to results from an NBC News Primary Poll. 

Forty-five percent of Arizona's Latino voters said they planned to support Biden, while 44 percent said they planned to support Sanders.

Among the state's Latino voters, 52 percent said the issue that mattered most to their vote is health care, followed by income inequality, race relations and climate change. Arizona's white voters were less likely to choose health care as the most important issue (44 percent), the poll found.  

A majority of Latino voters in the state also said they support replacing private health insurance with a single government plan for everyone, a notable part of Sanders' platform.

Fifty-four percent of Arizona's Latino voters identify as liberal; 46 percent identify as moderate or conservative. More of these voters are age 45 or older  (57 percent) than are under 45 (43 percent). 

Read more on the NBC News Primary Poll.

Arizona too early to call, NBC News projects

Arizona's Democratic primary is too early to call, NBC News projects.

As of 10 p.m. ET, NBC News has projected Biden the winner in Florida and Illinois. He now holds a commanding delegate lead of nearly 300 points and is more than halfway to clinching the Democratic presidential nomination.

Arizona sees high voter turnout despite coronavirus fears

The number of in-person voters in Maricopa County taking part in the state’s Democratic presidential preference primary today has surpassed the number who took part at the county level for the 2016 Democratic presidential preference primary, Maricopa County Elections Department spokeswoman Megan Gilbertson told NBC News.

Maricopa County accounts for more than half of the state’s registered Democratic voters. This is especially notable because the Democratic race was more competitive in and the high Democratic turnout took place despite coronavirus concerns and despite the county closing one-third of its polling locations over the weekend.

Biden wins Illinois, NBC News projects

Biden defeated Sanders on Tuesday in the Illinois Democratic primary, NBC News projects.

That's more good news for the former vice president, with NBC News projecting a big win for him in Florida over Sanders earlier in the evening. Results from Arizona's primary are still to come. 

According to the NBC News delegate count, Biden is now more than halfway to clinching the Democratic presidential nomination and has surpassed 1,000 delegates.

NBC News Primary Poll: Older, moderate and black voters drive Biden's win in Illinois

Joe Biden won Illinois' Democratic primary on Tuesday, beating Bernie Sanders with support from groups that have helped Biden claim other primary victories this year, according to an NBC News Primary Poll.

In Illinois, Biden won the support of voters age 45 and older, those who identify as moderate or conservative and black voters. 

He also won the support of Illinois voters who oppose Medicare for All, as well as those who said the quality that matters most in a candidate is someone who can unite the country and voters who said they are very concerned about the effects of the coronavirus outbreak. 

Read more on the NBC News Primary Poll.

Biden opens up commanding delegate lead over Sanders

WASHINGTON — Joe Biden is poised to walk away from Tuesday's primaries with a nearly insurmountable delegate lead over Bernie Sanders after winning Florida, one of the biggest states of the primary calendar, according to NBC News projections.

The former vice president now has 269 more delegates than the Vermont senator, 1,047 delegates to Sanders' 778, as of 9:00 p.m. ET.

Biden is now past the halfway mark to the 1,991 delegates he would need to win a majority of all delegates, and thus capture the Democratic presidential nomination.

Read the full story here.

Trump is now the presumptive GOP nominee, NBC News projects

President Donald Trump is the Republican Party's presumptive presidential nominee, NBC News projects.

NBC News made the call after projecting Trump the victor in the Florida and Illinois Republican primaries.

Those projected wins put him over the threshold of delegates needed to officially become the party’s nominee.