A federal judge on Thursday declined to postpone Wisconsin’s scheduled April 7 presidential primaries amid widespread worries that holding elections during the coronavirus pandemic could risk public health and curtail access to the polls.

The ruling from U.S. District Judge William M. Conley means Wisconsin will remain the only one of 11 states originally scheduled to hold contests in April that has not postponed or dramatically altered voting amid the pandemic.

However, in a 53-page ruling, Conley extended the deadline for absentee ballots to be requested by voters from Thursday to Friday, and extended the deadline for completed ballots to be received by local election officials by six days: from 8 p.m. on April 7 to 4 p.m. on April 13.

He also prohibited the state from enforcing the requirement that absentee ballot envelopes bear a witness signature when voters include a statement that they were unable to obtain one safely.

Conley made clear that he disagreed with the state’s decision to go forward with the election, but he explained that he was constrained to consider only the constitutional rights of voters — not public health.

“Without doubt, the April 7 election day will create unprecedented burdens not just for aspiring voters, but also for poll workers, clerks, and indeed the state,” Conley wrote. “As much as the court would prefer that the Wisconsin Legislature and Governor consider the public health ahead of any political considerations, that does not appear in the cards. Nor is it appropriate for a federal-district court to act as the state’s chief health official by taking that step for them.”

Conley also reserved the right to judge that voters’ rights have been infringed — something that he said could not be assessed until Election Day.

It is unclear what action he would take if he concluded that, as he wrote, “the actual voter turnout, ability to vote on election day or overall conduct of the election and counting votes timely has undermined citizens’ right to vote.”

Sen. Bernie Sanders (I-Vermont) this week urged state officials this week to postpone the contest, but former vice president Joe Biden told reporters Thursday that the question is “for the Wisconsin courts and folks to decide,” adding that he thinks it’s possible to hold an election during the pandemic with more mail-in balloting.

Voting-rights activists and local election administrators in Wisconsin painted a dire portrait of the risk of infection to poll workers and voters, saying how difficult it would be to administer elections under those circumstances.

More than 100 municipalities reported not having enough poll workers to open a single voting location. State officials predicted that tens of thousands of voters who have flooded election offices with mail-ballot requests in recent days were at risk of not receiving them on time.

Scott McDonell, the Dane County clerk, who spent Thursday distributing to city and town election officials masks, gloves and “170 proof” sanitizer cooked up by a local distillery, said his biggest concern is the likely spread of the virus on Tuesday. New projections place April 7 near the peak of Wisconsin’s coronavirus outbreak.

“I agree with the judge that it’s extremely dangerous for us to go forward with an election right as this pandemic is accelerating,” McDonell said. “But that’s what’s going to happen, so we’re planning the best we can right now to make it work on Tuesday.”

Leaders in the Republican-controlled legislature argued that moving the voting date so late in the process would sow confusion and create a leadership vacuum in cities and towns holding contests for municipal posts that will be vacant as early as mid-April.

Voting rights groups turned to the federal courts for intervention, supported by national Democrats and some county clerks in the state. National Republicans are helping defend the decision to go forward with voting next week.

A lawyer for the Republican National Committee and the Wisconsin Republican Party, Patrick Strawbridge, filed a notice of appeal soon after Conley issued his opinion. The Republican legislature filed an appeal Thursday, too.

“It is unprecedented to allow votes to be cast after Election Day has already occurred, and we are appealing the judge’s decision in order to uphold the integrity of our elections,” RNC national press secretary Mandi Merritt said in a statement.

The power to delay an election in Wisconsin lies with the legislature, but Scott L. Fitzgerald, the Republican majority leader in the Senate, and the Republican state House speaker, Robin Vos, noted that Gov. Tony Evers (D) did not push to postpone Tuesday’s vote, either.

“If I could have changed the election on my own I would have but I can’t without violating state law,” the governor said in a statement Wednesday night. “I’ve asked the legislature to do its part to ensure a fair and safe election and I hope we can get some clarity as soon as possible.”

Evers announced Wednesday that he will deploy the Wisconsin National Guard to help staff polling locations with sharp deficits of workers. Election officials have not yet been told how many soldiers will be deployed to each locality.

At a news conference Wednesday, Vos said he plans to volunteer at the polls on Tuesday, and encouraged others to do the same.

“I feel safe being there because of the safeguards being put in place by local governments and the Wisconsin Elections Commission,” Vos said. “If you’re bored at home and sick of watching Netflix, volunteer to go and help at the polls.”

Evers had previously asked for mail ballots to be sent to every registered voter. He also asked the legislature to lift photo ID requirements for mail-in voters, extend in-person early voting through the final weekend before the election and move back the deadlines for returning absentee ballots, as well as counting them. The legislature had rejected his requests.

“In the absence of the Legislature doing its part to ensure a fair and safe election, I appreciate that the court chose to implement some of the common-sense solutions that I’ve been advocating for,” the governor said in a statement Thursday. “It’s great news that Wisconsinites will have more time to request and submit a ballot and that clerks will have more time to count ballots. I continue to encourage every Wisconsinite to request their absentee ballot and vote safely from home.”

Now, with Biden holding a dominant lead in the delegate count against Sanders, state and local election officials said they expect a less robust turnout for the Democratic primary.

Democrats and voting activists have accused Republican lawmakers of trying to suppress voter turnout intentionally to help an incumbent candidate for the state Supreme Court, conservative Justice Daniel Kelly, keep his seat.

In late 2018, GOP lawmakers considered changing the date of the Democratic presidential primary, which was expected to draw high turnout, to protect Kelly’s candidacy. At the time, Fitzgerald said that moving the Democratic contest to March would give the justice a “better chance” of winning.

Matt Viser contributed to this report.