The Department of Justice wants "to preserve and segregate all ballots ranking" a candidate named Dan Sullivan for a potential investigation of whether voters in Alaska's U.S. Senate election mistakenly ranked him in the belief he was incumbent Republican Sen. Dan Sullivan, a federal prosecutor told a judge in a court filing late Friday.

The filing came in a lawsuit by the DOJ, which asks District Court Judge Sharon Gleason to block state election officials from immediately certifying the Senate election if Sen. Sullivan loses by a margin that might be attributable to voter confusion from the presence of the other Sullivan on the ballot. The DOJ wants to conduct an investigation to determine voter intent if the incumbent loses.

"Election Day is on November 3, 2026, which poses a substantial risk that the candidacy before us will mislead voters and ultimately result in an electoral process that lacks integrity," U.S. Attorney for Alaska Michael Heyman said in the filing, signed by one of his assistant prosecutors.

"The United States of America contends that the proposed precautionary measures will be impossible after Election Day, showing good cause for expedited consideration," the filing said.

Heyman earlier Friday told reporters at a press conference that there is an "ongoing" criminal investigation into how and why retired school teacher Dan Sullivan decided to run for the Senate for the first time this year.

The DOJ's suit, which President Donald Trump said he had requested, claims the "sole purpose" of the non-incumbent Sullivan running was to benefit the campaign of Democratic nominee Mary Peltola by reducing the number of votes for Sen. Sullivan.

"We will not let anyone or any group undermine this election," said Heyman at a press conference in Anchorage, which was held just four days before Election Day.

"There is both a civil investigation and a criminal investigation that is ongoing," Heyman said. "There is a surge of FBI resources and resources in this office."

"Every Alaskan deserves a fair election, and they're going to get one," the prosecutor said.

He said that the criminal probe has been underway for months. Heyman had previously recused himself from the probe because he was being considered for a judicial nomination, but that recusal was rescinded Thursday because he was no longer under consideration.

Heyman said the criminal investigation has been accelerated because of a New York Times report on Wednesday that said aides Peltola's campaign and senior aides at the Democratic Senatorial Campaign Committee helped recruit the retired teacher to enter the Senate race with the hope of drawing votes from the incumbent Sullivan.

"When credible information comes out, we are committed to pursuing that information … and we will act on it," Heyman said.

Peltola's campaign and the DSCC deny being involved in the retiree's Senate campaign.

Heyman, when questioned by reporters, would not say what criminal statute might have been violated

Earlier Friday, a federal judge kept on a fast track efforts to dismiss the DOJ's suit.

Judge Sharon Gleason ordered the DOJ to respond by 1 p.m. Alaska Time to the new dismissal motions, which were filed hours after the department amended its suit in U.S. District Court in Anchorage on Thursday to add a new legal claim.

The DOJ's updating of the civil complaint forced Gleason to rule the prior dismissal motions were moot.

Gleason gave state election officials, the campaign of Democratic nominee and other groups until noon Saturday to reply to the DOJ's response.

The judge's order leaves open the possibility that she will rule on the dismissal motions before Tuesday, which is Election Day, as both the state and Peltola's campaign have requested.

The state, the campaign, and other intervenors in the suit argue the DOJ has no legal authority to block certification of an election because two candidates on a four-candidate ballot happen to share the same name.

The winner of Alaska's race could determine which party holds a majority in the Senate starting in January. Republicans currently have 53 seats in the 100-member chamber.

Alaska's election uses ranked-choice voting. If no candidate obtains more than 50% of the vote in the first count, then the fourth-place finisher will be eliminated, and the second choice on that candidate's ballots will be allocated to the remaining candidates.

Only Peltola and Sen. Sullivan are considered likely to draw large shares of the votes.

The DOJ's suit seeks to delay certification of the Senate election if Sen. Sullivan loses by a margin that could be attributable to voter confusion over the presence of the other candidate, who is listed as Daniel J. Sullivan, on the ballot.

The amended complaint, which updates the suit filed Oct. 23, added a claim under the Supremacy Clause of the U.S. Constitution to the first claim, under the National Voter Registration Act.

It also contained added details from the Times article.

Peltola's campaign, in its dismissal motion filed Thursday, said, "Rather than defend its indefensible legal claims as it was ordered to do, the Department of Justice ... has filed an Amended Complaint that does nothing to address the fatal problems that preclude it from bringing this case or obtaining the relief that it seeks."

"The U.S. Constitution leaves the regulation of federal elections exclusively to the States and to Congress, and DOJ has no statutory authority to bring this case," the motion said.

In their own dismissal motion, state election officials said the amended lawsuit "rests on the same meritless theory that the National Voter Registration Act (NVRA) — a voter registration law — governs this case, which has nothing to do with voter registration."

"Because this reading of the NVRA fails, the amended complaint fails," the motion said.