Lipinski admitted in an interview last week he is combating a lot of unknowns. “We’ll see where the presidential primary is,” he told reporters in the Capitol. “You don’t know what’s going to happen, don’t know what the coronavirus — what impact that could have. So, just wait and see.”

The Newman campaign has urged supporters to vote early, is prioritizing phone banking and has canceled its election night party.

Both teams could make a plausible case that low turnout is to their benefit, depending on the age and ideology of who shows up. Lipinski’s team thinks he could have an edge with older voters, who tend to be more reliable and may be more likely to go to the polls.

Yet the coronavirus disproportionately affects those 60 and older and public health officials urged elderly people to remain in their homes as much as possible. Other liberal challengers, such Ocasio-Cortez, have won low-turnout races in which the electorate is smaller and more ideological.

The 2018 midterms brought roughly presidential-level primary turnout, and Newman came within 2,200 votes of ousting Lipinski. Though a new policy by the House Democratic campaign arm that blacklists consultants who work with primary challengers cost her some top campaign talent, Newman said she feels better prepared this cycle.

“As you can imagine, your first time, out you learn a lot. And I did. And there’s things that I didn’t do well," she told reporters in a phone call last week.

Now "we have an amazing voter outreach program," she said. "I started fundraising a lot earlier this time.”

Her campaign, she said, has knocked on more than 110,000 doors and made 90,000 phone calls. She had outraised Lipinski by more than $400,000 as of late February, and that contrast is shown particularly stark on television. Newman has spent about $900,000 on television advertising, while Lipinski has dropped less than $450,000, according to an analysis obtained by POLITICO.

Plus, a coalition of abortion rights groups, including EMILY’s List, NARAL Pro-Choice America, and Planned Parenthood, has dropped about $1 million in TV ads knocking Lipinski. And outside allies who spent for Lipinski in 2018, such as the bipartisan group No Labels, have largely stayed out this cycle, leaving a stark disparity.

“She’s got significantly more independent-expenditure resources than she had last time, and we have significantly less,” said Dave Heller, a media consultant for Lipinski, “which is the only reason why we’re worried.”

Lipinski is reviled by the liberal wing of the party for a slew of positions and votes that range from his support for defunding Planned Parenthood to his 2010 opposition to the Affordable Care Act. He is now notably running an ad touting his efforts to protect that law and attacking Newman for supporting a single-payer health care plan.

Still, Newman has centered her campaign on other issues like reducing gun violence and making health care affordable. She supports "Medicare for All" and the "Green New Deal."

Lipinski has pitched himself as more in line with the district and suggests Newman is too extreme: "We should remain focused on what’s important. What really holds us all together as Democrats: the type of agenda that we have had in the House with our majority in this Congress."

Yet there’s evidence to suggest his allies are leaning on independent and Republican voters to boost him in the Democratic primary. An internal campaign strategy document accidentally leaked in November suggested “GOP surrogates” could help Lipinski court Republican voters.

Then this weekend, a Newman volunteer received what appeared to be an automated text message mobilizing GOP-leaning voters to "stop" Newman and Cook County (Ill.) prosecutor Kim Foxx."

Asked last week about the possibility of courting Republican voters — Illinois doesn't have party registration, so voters can pull whichever party's primary ballot they request — Lipinski said it was not the focus of his outreach but suggested he would take their support.

“I think it’s good to have more people vote in the Democratic primary, bring them into the Democratic Party,” he said.

Lipinski was first elected in 2004, after his father, then-Rep. Bill Lipinski, announced his surprise retirement and persuaded the state Democratic Party to nominate his son to replace him on that fall's ballot. The younger Lipinski could benefit from Chicago machine politics that boosted him and his father in the past. He will need to run up the margins in the Chicago part of the district, as he did two years ago, while Newman is banking on support in the southwest suburbs.

A win by Newman on Tuesday would bring a surge of energy to progressives disheartened by a stinging loss earlier this month against Texas Rep. Henry Cuellar, who also opposes abortion.

Cuellar and his fellow moderates have hailed his victory over Cisneros, a 26-year-old immigration attorney, as an indicator that their caucus is still a big-tent party.

“It bodes well for moderates and centrists,” said Cuellar, who said he had discussed his race with Lipinski. “A lot of members were very happy I won because they felt that, if I would have lost, then that would have created a momentum.”

Sanders’ dismal performance in recent primaries has relieved some Lipinski supporters, who worried Sanders could drive out young and more left-leaning voters out to the polls, and that they would be more likely to support Newman.

Interviewed last week at the Capitol as the House scrambled to cobble together a program to tackle the coronavirus pandemic, some top progressives suggested they had not been closely monitoring Lipinksi’s race or were otherwise preoccupied.

"Obviously, I’ve been very busy with the Sanders campaign,” said California Rep. Ro Khanna a top Sanders surrogate. “But I’m supportive of her; we did some fundraising for her.”

“I don’t know any of the day-to-day detail stuff,” said Wisconsin Rep. Mark Pocan, a co-chairman of the Congressional Progressive Caucus who endorsed Newman, when asked if he were following the race.

The scaling back of large gatherings precluded any kind of final-weekend rally with big-name headliners like Sanders or Ocasio-Cortez — though it’s unclear whether any would have materialized without the outbreak. Neither campaigned for Cisneros in South Texas.

“I was always a little bit worried about this dynamic,” said Sean McElwee, the founder of liberal think tank Data for Progress. “The extent to which the top of the ticket was going to swamp out interest in the down-ticket stuff was always a danger for these primary challengers this cycle.”