Pro-democracy advocates on Saturday vowed to ensure all Wisconsin voters are permitted to vote in the 2020 election after a state judge ordered more than 200,000 voters to be purged from the rolls.

The state had sent letters to 234,000 people who were believed to have moved, who were told they would be removed from voting lists if they did not respond within 30 days—but that the purge would not take place until 2021.

Conservative group Wisconsin Institute for Law & Liberty filed a lawsuit, saying the voters should be removed from the rolls before the next general election.

According to the Milwaukee Journal-Sentinel, 55% of the voters who were sent letters were in districts which Hillary Clinton won in 2016, including many in the state's two largest cities and in college towns.

Former Attorney General Eric Holder said the right-wing effort to create confusion among likely-Democratic voters in a state where President Donald Trump won by less than 23,000 votes in 2016 was "expected unfairness" from the conservative group.

Here they go. Voter purge in Wisconsin that disproportionately targets Democrats, people of color and those who voted for Hillary in 2016. The expected unfairness. Fight this Wisconsin! Fight for a fair election. https://t.co/lAKTHbwyBW — Eric Holder (@EricHolder) December 14, 2019 Why does the right wing go to such extreme lengths, and do so much, to eliminate voters, make it difficult to vote, tamper with the electoral infrastructure? Exactly what do some on the right fear? If you can’t win elections fairly-maybe you need to change your philosophy/ideas. https://t.co/jtFqRplvs9 — Eric Holder (@EricHolder) December 14, 2019

Ben Wikler, chair of the Wisconsin Democratic Party, called the purge a "product of a right-wing legal and political strategy to prevent eligible voters from voting."

"It should be a concern to anyone who believes in the core idea of democracy," Wikler said, but he noted on Twitter that voters whose names are removed from rolls can still re-register in the state, including on Election Day. He called on voting rights advocates to help make sure purged voters get to the polls in 2020.

"Now our job is to organize harder than they can suppress," Wikler said.

A right-wing lawsuit triggered a 200,000-voter purge in Wisconsin yesterday. But we still have same-day registration in this state. So now our job is to organize harder than they can suppress. https://t.co/jDF89Xn7Mr — Ben Wikler (@benwikler) December 14, 2019 A) read this thread and learn the facts

B) key thing is, we still have same-day voter reg in Wisconsin. So we can still help purged folks vote. In other words: don’t panic. Organize. https://t.co/trLEhsTxoJ

C) able and willing to chip in? Thank you! https://t.co/wRSt7EtOgD https://t.co/F021Dd78R0 — Ben Wikler (@benwikler) December 14, 2019

The League of Women Voters and election officials said they would fight the judge's decision in court.