The United States Department of Justice has filed a lawsuit seeking to delay certification of Alaska’s Senate election result if Republican incumbent Dan Sullivan narrowly loses to Democrat Mary Peltola in the November 3 midterms.

The reason? Another candidate named Dan Sullivan is also on the ballot.

In a lawsuit filed on Thursday, the department argued that the second Sullivan, a retired teacher who registered as a Republican, is deliberately trying to confuse voters.

Alaska’s Supreme Court has already ruled that both candidates may remain on the ballot.

So who are the two Dan Sullivans, and what could the lawsuit mean for the election?

What is happening in Alaska’s US Senate race?

Senator Sullivan is seeking a third six-year term in the race against Peltola, a former congresswoman who became the first Alaska Native elected to the US House of Representatives in 2022.

Alaska has traditionally voted Republican in presidential elections. President Donald Trump won the state by roughly 13 percentage points in 2024, but this year’s Senate race appears more competitive.

In August’s primary, Peltola received 49.5 percent of the vote, compared with about 41 percent for Senator Sullivan.

Two other candidates advanced to the November 3 election: Daniel J Sullivan Jr and Gerald Heikes.

Who are the two Dan Sullivans?

Dan S Sullivan was first elected to the US Senate in 2014 and was re-elected in 2020. He previously served as Alaska’s attorney general and commissioner of natural resources.

Daniel J Sullivan Jr is a retired elementary schoolteacher and a former US Forest Service employee from Petersburg in southeastern Alaska.

His entry into the race this year prompted accusations from Republicans that he was trying to confuse voters, something he has denied.

Alaska election officials initially disqualified him, but the state’s courts overturned the decision. In June, the Alaska Supreme Court allowed him to remain on the ballot.

The ballot identifies the incumbent as “Sullivan, Dan S (Registered Republican) Incumbent” and the other candidate as “Sullivan, Daniel J Jr” without a party designation, even though he has registered as a Republican.

Glenn Wright, a political science professor at the University of Alaska Southeast, told Al Jazeera that voters should have no problem recognising each candidate.

“The ballots are super, super, super clear about who the incumbent Dan Sullivan is,” he said.

But Forrest Nabors, chairman of the political science department at the University of Alaska Anchorage, said the similar names could still affect the result.

“It could swing the election if the election is close and the margin of voters who intend to re-elect the senator are confused and accidentally vote for the other candidate named Sullivan,” he told Al Jazeera.

Why has the Justice Department filed a lawsuit?

The Justice Department sued Alaska in federal court on Thursday, arguing that having two candidates with similar names could mislead voters.

It wants the state to be prevented from certifying the result if the Republican senator loses by fewer votes than his namesake receives, pending an investigation into possible voter confusion and whether voters mistakenly supported the wrong Sullivan.

The lawsuit cited the National Voter Registration Act, a federal law governing voter registration.

Nabors described the Justice Department’s intervention as “unusual” but said there could be circumstances in which federal action is justified.

“It’s perhaps not unreasonable,” he said, adding that federal intervention could be justified when an election is administered unfairly.

“Whether voters are confused and erroneously vote or not is a question that is hard to measure,” he added.

Wright questioned the basis of the lawsuit at all, however.

“The legal filing is either, you know, a filing in bad faith, or it’s a filing that misunderstands the way that Alaska’s election system operates,” he said.

How does Alaska’s ranked-choice voting system work?

Unlike most US states, Alaska allows voters to rank candidates in order of preference rather than voting for just one.

The four candidates with the most votes in the primary advance to the general election, regardless of party.

If nobody wins more than 50 percent of the first-choice votes, the candidate with the fewest votes is eliminated. Their votes are transferred to the next-ranked candidates still in the race. This continues until two candidates remain, and the one with the most votes wins.

Wright said the system helps prevent candidates with a smaller support base from splitting the vote.

“It’s supposed to eliminate the spoiler effect,” he explained.

For example, if a voter mistakenly chooses Daniel J Sullivan Jr but ranks the incumbent second, their vote could eventually transfer to the senator.

“The system is actually designed to cope with this sort of a thing,” Wright said.

However, voters are not required to rank every candidate, meaning some votes may not transfer.

Can the federal government block certification of the results?

The Justice Department may ask a federal court to intervene, but it may not independently stop Alaska from certifying the results.

The lawsuit seeks to delay certification if the Republican incumbent loses and votes cast for the other Dan Sullivan could have changed the outcome.

Derek Muller, an election law professor at the University of Notre Dame, questioned how officials would determine which candidate a voter intended to support.

“The best evidence that voters preferred one Sullivan over another is how they marked their ballots,” he wrote on the Election Law blog.

Muller also questioned the legal basis of the lawsuit.

The Justice Department cited the “findings and purposes” section of the National Voter Registration Act, which lists protecting “the integrity of the electoral process” among the law’s purposes.

But Muller argued that the department was treating that statement as a legal obligation, even though the law says nothing about which candidates may appear on a ballot.

He described the argument as “so absurdly thin” that there was “essentially no likelihood of success”.

He also questioned why the department had waited until days before the election to intervene when the dispute over the two candidates had been known for months.

Nabors said the case could still affect voters even if the courts do not decide it before election day.

“Whether the lawsuit is adjudicated in time, it will at least drive awareness of the problem among voters, which might limit the numbers of those who vote erroneously for the other Sullivan,” he told Al Jazeera.

No federal court has ordered Alaska to suspend certification.

What does this mean for the midterm elections?

Alaska’s Senate race could play a part in deciding which party controls the upper chamber of the US Congress.

Republicans now hold 53 of the Senate’s 100 seats while Democrats and two independents who caucus with them hold 47. Democrats need a net gain of four seats to reach 51 and secure a majority.

A 50-50 split would allow Vice President JD Vance to cast tie-breaking votes in the chamber.

“The defeat of Senator Sullivan would also take away an important senator from the Republican caucus. He has been influential in foreign policy and energy policy,” Nabors said.

Wright said the competitive race in such a traditionally Republican state reflects wider dissatisfaction with the Trump administration.

“The fact that the Alaska race has come to be competitive is a real indicator of how difficult the road is for a lot of Republican candidates in the current, kind of public opinion environment,” Wright said.

The lawsuit has also raised questions about whether the Trump administration could challenge certification in other states in which Republicans lose.

The Justice Department is already facing criticism over investigations and prosecutions involving Democratic opponents of Trump.

Federal agents have recently searched the home of Democratic Representative Ilhan Omar as part of an immigration fraud investigation. Omar has described the action as politically motivated.

Trump has acknowledged directing the Justice Department to file the Alaska lawsuit while his administration maintains that the action is intended to prevent voter confusion.