As New Hampshire voters headed to the polls Tuesday for the critical first-in-the-nation primary, WGBH News reporters fanned out to track the candidates and cover the events that may reshape the 2020 presidential election campaign.

4:00 p.m.

A voter decides!

At a Bernie Sanders rally Monday night, Rebecca Nash Pannella told WGBH News' Tori Bedford that she was still trying to decide who to vote for (see below). Tuesday afternoon she emailed her decision:

"I got home and was so wired that I spent some time on Politico etc. comparing my finalist candidates. I went to bed thinking I'd vote for Bernie.I got up this morning and took a few minutes to step back from the adrenaline and reassess. I chose Amy Klobuchar because, for me, it's time for a woman to be President. She is smart, qualified, baggage-free, a great debater and can win (and who I'd most like to have coffee with...).I'm very thankful that this decision was so hard for me to make. It gives me hope that the Dems depth will strengthen us as a party and a country. "

While Klobuchar has been collecting much of the buzz around New Hampshire, there are still voters rallying around candidates at the lower end of the polls.

Calley Milne of Manchester said "I voted for Michael Bennet, a total outlier, but I'm super excited for him. I’m hoping he gets traction in New Hampshire today where, you know, being the first-in-the-nation primary, it's an opportunity to give somebody the opportunity to get on the national stage . . . I believe in him wholeheartedly."

And of course the Yang Gang is still out in force.

2:00 p.m.

What is the Republican Party’s dream scenario for 2020? Former trump campaign manager Corey Lewandowski offered a hint Tuesday. On WGBH’s Boston Public Radio, Lewandowski predicted a Bernie Sanders victory in the Democratic primary and praised Sanders as “a guy who has a phenomenal fundraising base. This guy knows how to raise money. He has massive crowds."

But Lewandowski said he thinks the “elites” in the Democratic party will use “superdelegates” to deny Sanders the nomination. “If they take this nomination away from Bernie because he doesn't get to the requisite number of delegates for their convention, and they decide they are going to hand it to Michael Bloomberg, there will be a revolution in the Democratic party” and President Trump will be set up for a landslide victory.

But there are Sanders supporters in New Hampshire think Trump should be afraid of him.

“As far as the issues go, I think it's most important to be authentic as a candidate to me. And I think being a billionaire and waking up and deciding to be a candidate is not something that's appealing to me,” said Esad Fazlic of Bedford.

Fazlic said he voted for Sanders four years ago and plans to again. “He's willing to go against not only in the Republican Party, but against his own party at certain times. So he's just very authentic and he's somebody that appeals to me.”

Meanwhile, Minnesota Sen. Amy Klobuchar toured polling places around the state and touted her victory in last night’s small-town midnight voting.

Three New Hampshire towns held midnight votes this year: Dixville Notch, Millsfield, and Hart’s Location. All told, 38 votes were cast in the Republican primary, with President Donald Trump receiving 31 of them. 27 total votes were cast for Democrats, with Klobuchar’s eight leading the pack. Elizabeth Warren and Bernie Sanders came in tied for second with four votes each.

12:00 p.m.

Former Vice President Joe Biden's campaign announced that he is leaving the state and will be holding an event in South Carolina at about the time the New Hampshire results begin rolling in Tuesday evening. The South Carolina primary is Saturday, Feb. 29. That doesn't suggest they are expecting the new Hampshire results will give them a lot to celebrate.

Even walking into the polls, some voters told our reporters they still weren't sure who they were going to vote for.

Jessica Schneider, a physician from Bedford, said "There are a couple of candidates that tick a few of my boxes, so I'm going to just go with my gut when I get in there."

This echoed a theme around the state all weekend — New Hampshire's Democratic voters decide late. At a Bernie Sanders rally Monday night, Rebecca Nash Panella of Portsmouth was still trying to make up her mind. "I don't know when its going to click for me," she said. "I know who I'm not going to vote for but I do not know who I'm going to vote for."

There is also a Republican primary Tuesday, and President Trump is expected to win handily.

But Joe Marrone of Merrimack told WGBH News "As a registered Republican, I like what the Republican Party stands for. But Mr. Trump has proven to be, you know, just an outrageously, you know, irresponsible, immature representative of our country. And so for me, I don't want to see him back in office, even though I'm not a Democrat.” Marrone said he thinks highly of former Massachusetts Gov. William Weld, who is runing against Trump.

10:30 a.m.

Minnesota Sen. Amy Klobuchar stopped by the WGBH News Morning Edition set and told host Joe Mathieu she thinks her background makes her the best candidate to compete with President Trump in midwestern swing states.

"The Midwest is not flyover country to me – I live there," Klobuchar said. Trump grew up rich and Klobuchar grew up in a working class family, she said "Our backgrounds couldn't be more different." Midwestern voters, she said, "are my friends and they are my neighbors."

The candidates are all repeating a theme our reporters say they have heard on the ground in New Hampshire all weekend: Democratic voters' top priority is picking a nominee who can win in November.

Sen. Elizabeth Warren, meeting voters at a polling place in Portsmouth, told reporters, “It just feels like we could really make this change ... And when somebody says ‘I voted for you then,' wow. That’s like a real concrete step. And that’s what we’re going to stay after, everyday.”

Meanwhile, Trump was tweeting Tuesday morning about his Monday night rally in Manchester. The Associated Press reported his advisors had hoped the security arrangements for the rally would complicate travel around Manchester for Democratic candidates.

9:00 a.m.

Former Vice President Joe Biden appeared on WGBH News' Morning Edition and emphasized his ability to both win the White House and help Democratic House and Senate candidates in swing states.

"You gotta figure out whose going to be able to go on and win in Pennsylvania" and other Rust Belt states that Donald Trump carried in 2016, Biden said, but the nominee also has to be “value-added to these frontline states.” Biden emphasized his success in 2018 campaigning for swing state Democrats who helped win control of the House of Representatives. "I went into 24 states that were purple and red states in the '18 election," Biden said, campaigning for 65 Democratic candidates. "And we won back the House."

Biden also said that he is not worried about his poor showing in the Iowa caucuses last week or the possibility of a third- or fourth- place showing in New Hampshire because he expects to do well in South Carolina and Nevada, with a heavier concentration of African-American and Hispanic voters.

Colorado Sen. Michael Bennet, who has barely registered on public opinion polls, also said he thinks his agenda could win 55 Senate seats for Democrats. "We have continued to lose those seats to Donald Trump, and I think its because we haven't been proposing an agenda that travels too well off the two coasts," he said.

WGBH News' Tori Bedford, Adam Reilly, Craig LeMoult, Edgar B. Herwick III and Saraya Wintersmith contributed to this report.