MADISON, Wis. — Democrats in the key swing state of Wisconsin vowed Monday to double down on efforts to ensure that any voters whose registrations are nullified by a judge's recent ruling will be able to register again before the 2020 presidential election.

Legal appeals could delay for months the judge's order Friday to immediately purge more than 200,000 voters who didn't respond within 30 days to letters seeking to confirm their addresses. The case is expected to go all the way to the Wisconsin Supreme Court, which is controlled 5-2 by conservatives.

The Wisconsin Democratic Party will use the state open records law to obtain the names of everyone who is purged and then target its efforts to “systematically” contact those most likely to be Democrats so they can re-register, said state party chairman Ben Wikler. Voters do not register by political party in Wisconsin.

“This is an organizing challenge, not a crisis,” Wikler said. He said purging the voters “just adds to our to-do list. It’s a reason to work, not to freak out.”

Even if the number of voters who didn't move but are tossed from the rolls is small, Democrats fear the impact on the election could be huge. President Donald Trump carried the state by fewer than 23,000 votes in 2016.

“I won the race for governor by less than 30,000 votes,” Democratic Gov. Tony Evers tweeted on Friday. “This move pushed by Republicans to remove 200,000 Wisconsinites from the voter rolls is just another attempt at overriding the will of the people and stifling the democratic process.”

The League of Women Voters of Wisconsin, which sought to intervene in the lawsuit but was rejected by the judge on Friday, is also looking into ways to assist people who may be purged, said the group's executive director, Erin Grunze.

The Wisconsin Elections Commission, which has an equal number of Republicans and Democrats, debated a GOP-offered motion Monday that would have required the purge to happen within seven days of the judge entering his order. It died, on a party-line 3-3 vote, with Democrats arguing it made no sense to immediately purge the voters given that appeals were likely.

The judge's ruling was a win for conservatives, who argued that state law requires the elections commission to deactivate voters who didn't respond within 30 days to a mailing sent in October flagging them as potentially having moved. The commission wanted to wait to remove anyone until 2021, citing problems in 2017 when voters who had not moved were tossed off the rolls.

The judge refused a request from the state Department of Justice to put his ruling on hold. He had not filed a written ruling as of midday Monday, a step that has to happen before any appeal can be filed or any voters can be purged.

Democrats on the elections commission said it was cavalier and political grandstanding to try and force the purge to happen within a week of that order given the expected appeals. But Republican Commissioner Bob Spindell said it was an “outrage” to keep more than 200,000 people on the rolls who shouldn't be there.

“Are we going to keep people on the rolls who shouldn’t be there or are we going to have clean election rolls?” Spindell said.

The affected voters were identified as having potentially moved, based on a review of documents indicating that they did, such as state Division of Motor Vehicles records. Milwaukee and Madison, the largest cities and base of Democratic support, account for 23% of the letters that were sent to voters who may have moved, based on a Milwaukee Journal Sentinel analysis. More than half of the letters went to voters in municipalities where Democrat Hillary Clinton defeated Trump in 2016, the analysis found.

Wikler said the Democratic Party had already identified voters who had likely moved to be contacted to re-register. Having the list of those targeting for purging just provides another data point to help Democrats find voters who need to update their registration, he said.

The number of voters who would be purged would be something less than the 234,000 who received the mailings. Anyone who responded within the 30-day window to affirm that they still lived at their current address or had moved and already re-registered would not be deactivated. As of Dec. 5, nearly 29,000 voters had done that, but it's unclear how many were within the 30-day window. That leaves about 215,000 others who likely face deactivation.

Wisconsin allows same-day voter registration, but it requires photo ID and proof of address. Wisconsin has about 3.3 million registered voters out of about 4.5 million people of voting age.