A federal judge on Sunday dismissed a Justice Department lawsuit that sought to block the certification of Alaska’s U.S. Senate race if Republican incumbent Dan Sullivan were to lose. The lawsuit was prompted by the presence of a second candidate with the same name, Dan J. Sullivan, on the ballot.

US District Court Judge Sharon Gleason stated in her order that the relief sought by the United States was "infeasible" because many voters had already cast their ballots. She also noted that the government offered no workable plan for segregating and investigating votes for Daniel J. Sullivan without violating voter privacy.

The Department of Justice, attorneys for the state, and the campaign of Democratic challenger Mary Peltola did not immediately respond to requests for comment.

Sullivan, who is running against Peltola in a closely watched race, had expressed concern that the other Dan Sullivan would siphon votes. He suggested that Peltola's campaign had been involved in recruiting the decoy candidate to confuse voters, a claim Peltola's campaign has denied.

"I’m sure I’m going to lose a lot of votes to that trickery," Senator Sullivan told CNN earlier on Sunday. He also doubted claims by Peltola that her top aides were unaware of the recruitment efforts for Dan J. Sullivan.

Dan J. Sullivan, a retired teacher, entered the race in June and had no contact with the Peltola campaign about running, according to his earlier statements. He has not responded to recent inquiries. Both Sullivans appear on the general election ballot, with the senator listed as Dan S. Sullivan, Republican, and the challenger as Daniel J. Sullivan, unaffiliated.

State courts, including the Alaska Supreme Court, had previously rejected efforts to remove Dan J. Sullivan from the primary ballot. He secured approximately 2.5% of the primary vote, qualifying him for the ranked-choice general election.

Attorneys for the Alaska Department of Law, representing state election officials, argued in a filing that the federal government's complaint was "meritless." They contended that Alaska had taken steps to distinguish the two candidates and that voters could seek assistance or consult election pamphlets if confused.

Last Thursday, the Justice Department escalated a criminal investigation into the presence of Dan J. Sullivan on the ballot, issuing grand jury subpoenas. The FBI also began contacting donors to Dan J. Sullivan, inquiring if they had been misled about their support.

Judge Gleason's ruling noted that the Trump administration's attempt to block certification conflicted with the Constitution's grant of election authority to states. She also referenced the Supreme Court's Purcell principle, which advises federal courts against altering election rules close to an election.