In the end, it wasn’t even close.

Less than a week after forcing Wisconsin voters to risk their health and go to the polls, Wisconsin Republicans suffered a stunning defeat on Monday night.

Daniel Kelly, a conservative justice on the state supreme court, lost his seat to Jill Karofsky, a liberal challenger, by more than 163,000 votes. Such a wide margin is remarkable in Wisconsin, where a race for a different state supreme court seat was decided last year by just 6,000 votes.

The election served as an early litmus test of Donald Trump’s political strength in Wisconsin, a state he critically needs to win in November. And it was the most significant test so far of whether a state could hold a fair election in the middle of the Covid-19 pandemic. Republicans in the state refused a last-minute request to delay the election. That decision was widely seen as a cold political calculation – fewer people would turn out to vote in person, which would benefit Kelly.

Ultimately, that calculation was wrong. Turnout was just over 34%, the highest for a spring election in the state since 2016, when both parties had competitive presidential primaries. It was only the second time in over half a century that a challenger defeated an incumbent for a seat on the state supreme court, according to the Milwaukee Journal Sentinel. Karofsky’s victory means the conservative majority on the supreme court will narrow from 5-2 to 4-3.

‘Isolation might have fostered higher voter turnout’

The election offers a strong rebuff to Trump, who insisted that Democrats wanted to postpone the election and move to an entirely vote-by-mail contest to boost their political chances. Trump has also repeatedly, and falsely, claimed that mail-in balloting leads to widespread voter fraud – there is no evidence of that in Wisconsin or elsewhere – and that it only benefits Democrats.

It’s more likely that Democratic turnout benefited from the party’s presidential primary being on the ballot. And at a time when Americans are spending more time consuming news at home, the controversy over whether to hold the election may have actually wound up encouraging voters, said Barry Burden, director of the Elections Research Center at the University of Wisconsin-Madison.

“Ironically, isolation at home might have fostered higher voter turnout,” he said.

Voters make their choices in Milwaukee last week. Photograph: Mike De Sisti/AP

But the election still came at a high price and probably disenfranchised many voters. People waited hours in line in Milwaukee, Green Bay and Waukesha to vote on election day, even as the state was under a formal stay-at-home order. State health officials are tracking whether holding in-person voting led to more cases of Covid-19.

‘It raises serious concerns for the future of our democracy’

“Although we were successful in this race, the circumstances under which this election was conducted were simply unacceptable, and raise serious concerns for the future of our democracy,” Karofsky said in a statement on Monday evening. “Too many were unable to have their voices heard because they didn’t feel safe leaving their home or their absentee ballots weren’t counted.”

In an interview on Tuesday, Karofsky said she was still hearing from voters who were unable to vote because they never received an absentee ballot or did not feel comfortable going to the polls. Even though she won, she said she still believed the election should have been moved.

“Their voices matter no matter what the result was yesterday,” she said of disenfranchised voters. “I do not think it can ever happen again. We can never have the type of voter suppression that we had last week, which resulted in people having to make an impossible choice between voting and staying healthy or alive.”

Karofsky added she thought last-minute Republican maneuvering around the election only reinforced the anti-corruption message her campaign pushed. “When it happens that quickly, it’s really easy for people to see what’s going on,” she said.

Charles Stewart, a political science professor at MIT who studies elections, said that voter turnout in Milwaukee county was between 35,000 and 50,000 votes short of what it “should” have been compared with other counties.

“It’s clear that turnout would have been greater in towns like Milwaukee and Green Bay had in-person election day voting not collapsed,” he said. “I think this race showed the value of the belt-and-suspenders approach of making mail voting available for everyone who wants it, but still maintaining as much of an in-person program as possible.”

There is a nationwide push to prepare for a mail-in election in November, and the Wisconsin contest offered a case study of the challenges. State officials got an unprecedented 1.2 million people to request mail-in ballots through early and consistent public messaging. But the flood of requests overwhelmed local clerks, who were unable to issue ballots promptly. Reports of people who requested ballots but never received them were being investigated by the Wisconsin elections commission and US Postal Service.

‘Voter suppression might not be as clever as Republicans think it is’

Wisconsin’s election highlighted the way last-minute court rulings and changes can bring havoc. Days before election, a federal judge extended the deadline to receive absentee ballots, but on the eve of the election, the US supreme court stepped in and added a requirement that ballots be postmarked by election day. That ruling caused enormous confusion after ballots started arriving at election offices without postmarks, disenfranchising voters who had put their ballots in the mail close to election day. It’s still not clear how many viable ballots were thrown out.

The contest also illustrated how severely Covid-19 can curtail in-person voting. In Milwaukee, city election officials faced such a shortage of poll workers that they closed down all in-person voting and offered just five locations to vote on election day, compared with the usual 180. Turnout in the city dropped 20 points from 2016.

“It is indisputable that thousands upon thousands of voters were disenfranchised,” said Ben Wikler, chair of the Wisconsin Democratic party. “Voter suppression might not be as clever as Republicans think it is. It can backfire by pissing voters off.”