MADISON, Wis. (AP) — Wisconsin Gov. Tony Evers plans to change the date of the special election for an open congressional seat because he was told by the U.S. Department of Justice that the dates he set last week violated federal law.

The election is to replace Republican Sean Duffy, who resigned on Sept. 23. That day, Evers set the special election for Jan. 27, with the primary scheduled for Dec. 30.

State and federal laws conflict on when the dates should be set, creating an “impossible situation,” Evers’ spokeswoman, Melissa Baldauff, said Tuesday.

“To follow state law would have violated federal law no matter what,” Baldauff said. “It is impossible to satisfy both state law and federal law at the same time.”

Wisconsin law requires primaries to be held 28 days before special elections. Evers complied with that law by setting the primary for the Jan. 27 special election on Dec. 30.

However, federal law requires military and overseas voters to obtain absentee ballots at least 45 days before any election for federal office. That conflicts with the state law calling for special election primaries 28 days before the general.

Evers is in consultation with both the state and federal departments of justice to set the new special election dates, Baldauff said.

“We want to announce something as soon as we can,” she said. “We just want to make sure there won’t be any additional confusion for municipal workers, the voters and the candidates.”

Evers is considering two different scenarios, both of which would move the general election to April or May.

Under one, the general election would be held on the April 7, the same day as the state’s presidential primary and state Supreme Court election. The primary for the special election would be Feb. 4, two weeks before the primary for the Supreme Court race and a host of local offices.

Under the other scenario, the primary would be Feb. 18, which is the date of the primary for the state Supreme Court race. The general election for the special congressional election would then be May 5.

Evers can’t align the special election with the same primary and general election dates as the regularly scheduled state spring elections because of timelines in federal law for certifying the results and having ballots available, Baldauff said.

The Wisconsin Legislature in 2011 changed the date of the state’s primary for fall elections from September to August to be in compliance with the 2009 federal law giving military and overseas voters more time to vote. But the Legislature did not change the law relative to special elections, creating the conflict for this race. This is the first time the issue has come up in Wisconsin since the federal law changed in 2009.

On Friday, the state Assembly Speaker Robin Vos asked Evers to change the election dates because the Dec. 30 primary would fall on the final day of Hanukkah. Baldauff said the decision to change the dates had nothing to do with the Vos request.

Three Republicans have announced their candidacies in the heavily GOP district that covers central, northern and northwestern Wisconsin. They are Tom Tiffany, a state senator from Minocqua, Jason Church, an Army veteran who lost both his legs in Afghanistan and worked as an aide to U.S. Sen. Ron Johnson, and Michael Opela Sr., who lives on a hobby farm in Edgar.

Church said in a statement that “Evers’ political motivations have resulted in chaos and uncertainty for voters.”

Tiffany said in a statement that “it is imperative that all military and overseas voters have the opportunity to vote” and he’s prepared to win no matter the election date. Opela did not immediately respond to a request for comment.

The winner of the special election will serve out the remainder of Duffy’s term but would have to run again in the fall of 2020 to serve a full two-year term.

Duffy resigned to be with his family after the birth of his ninth child, who was diagnosed with heart defects. Duffy posted on Facebook on Monday that his wife had been admitted into the hospital and the baby was “coming any moment.”