Three states forged ahead with consequential Democratic presidential primaries Tuesday as the coronavirus grinded regular American life to a halt and one of their counterparts shut down voting.
Arizona, Florida, and Illinois are holding nominating contests — with some modifications to reduce the risks from the pandemic. On Monday night, Ohio officials said the state would not open polls Tuesday due to "unacceptable risk," after a judge denied a push to delay its primary until June.
Biden pulled ahead of the Vermont senator with strong showings in two rounds of primaries on March 3 and 10, helped along by a handful of his ex-rivals dropping out and endorsing him. He has led Sanders by big margins in recent polls of the states voting Tuesday, meaning he could build a near insurmountable delegate edge once they cast their ballots.
If Biden wins the elections, particularly by wide margins, "it's effectively the end of the primary process for the Democrats," said Herb Asher, a professor emeritus of political science at the Ohio State University.
"I don't know if Bernie Sanders will see it that way," he added.
By the time Tuesday's contests dole out their spoils, states will have allocated more than half of pledged delegates in the Democratic race. Heading into the day, Biden leads Sanders by 871 to 719 delegates, according to NBC News. A candidate needs 1,991 delegates to clinch the nomination.
The three states voting Tuesday will award 441 pledged delegates combined. They break down:
Sanders got his last major chance to reset the race Sunday night in a one-on-one debate with Biden. The event, moved to CNN's Washington studios from Arizona and conducted without an audience, carried many traces of the pandemic's effects. The rivals bumped elbows at the start instead of shaking hands and stood at lecterns spaced out farther than usual.
While Sanders drilled into his case that Americans need universal health care during the pandemic and sharply criticized his competitor's record on Social Security and the Iraq War, Biden avoided the kind of meltdown that might cost him a major share of votes Tuesday.
In a statement Tuesday, Sanders communications director Mike Casca said the campaign is not doing normal get out the vote efforts in the primary states.
"We are making clear to voters that we believe going to the polls amid the coronavirus outbreak is a personal decision and we respect whichever choice they make. We are also passing along guidance from the CDC on staying safe during the crisis," he said.
Even as other states began to push back primaries, the three voting Tuesday moved forward with their elections. Ohio Gov. Mike DeWine recommended Monday that his state delay its primary until June and filed a lawsuit to make the change. A judge rejected the request Monday night, but the state said it would close its polls anyway.
The states voting Tuesday took steps to reduce coronavirus risk. For example, Florida moved polling sites away from high-risk areas such as nursing homes and hospitals.
Illinois Board of Elections spokesman Matt Dietrich said Monday the state took steps to ensure safety, including by encouraging early voting over the weekend to reduce crowds Tuesday. He said the state had seen 504,000 early votes cast and 294,000 mail ballots sent to voters, up from 400,000 and 160,000, respectively, in 2016.
In explaining why Illinois moved forward with the election, he said "there is no date in the foreseeable future when we can expect greater safety with any certainty."
The pandemic could affect turnout. Biden fares better with older voters, who typically are reliable voters but are more vulnerable to the coronavirus disease. Sanders also outperforms his rival among college students, many of whom will have gone home after their schools shut down operations.
Biden pushed to keep voter participation up as the pandemic spread. On Sunday, he tweeted that "if you are feeling healthy, not showing symptoms and not at risk of being exposed to COVID-19: please vote on Tuesday."
He told voters that if they have showed symptoms of the disease or are vulnerable to it, "absentee or vote by mail options are the best way to make your voice heard, while protecting your neighbors."
— Graphics by CNBC's John Schoen