The US Justice Department has filed a pre-emptive lawsuit asking a federal court to block certification of Alaska’s Senate election on 3 November if Republican incumbent Dan Sullivan is defeated.

The suit argues that an independent candidate on the ballot named Daniel J. Sullivan — a retired teacher — could confuse or mislead voters looking to vote for the senator. It asks the court to delay certification pending an investigation if Senator Sullivan loses by a margin smaller than the number of votes cast for his same-named rival, CNN reported.

President Donald Trump took credit for the challenge. “Well, I’m the one that said ‘do it,’” he told reporters in Florida on Friday. Attorney General Blanche said it was “not DOJ’s intention to improperly interfere with elections,” according to Al Jazeera.

A contest that could decide the Senate

Senator Sullivan faces former Democratic congresswoman Mary Peltola in a race that could determine control of the chamber. Polling has been sparse, though Hiru News reported that recent surveys put Peltola narrowly ahead.

The independent Sullivan rejects the claim that he entered to split the Republican vote, saying voters should be free to choose their candidate.

Election law specialists were sceptical. Derek Muller of Notre Dame Law School called the theory “strange and unusual” and said it was unclear how a court could intervene as the department proposes. Lauren Miller Karalunas of the Brennan Center for Justice noted that certification is run by states, not the federal government, and carries built-in safeguards.

The Alaska Supreme Court rejected an earlier attempt to remove the independent candidate from the ballot in June.