He blended in as well as one can in a town where everyone knows just about everyone else. He was not campaigning. “I didn’t want to turn it into something that was about me rather than about the celebration,” he said.

This Sullivan — Dan. J — has been an unconventional candidate from the start. He drew intense, immediate blowback for having the same name and party affiliation as the senator — Dan. S. — in a race that could help decide control of the Senate in November. The incumbent and GOP allies accused the same-named challenger in the Aug. 18 primary of being a sham candidate working with Democrats to sow confusion and help Peltola. Dan. J. Sullivan and the Peltola campaign have denied that claim.

A top state elections official booted Dan J. Sullivan from the ballot. The Alaska Supreme Court later ordered that he be included.

All candidates, including independents, run in one primary in Alaska. The top four vote-getters advance to the ranked vote general election in November. Primaries in the top races can be crowded, with more than a dozen candidates. Dan. J. Sullivan is among 16 hopefuls in the Senate race. The incumbent and Peltola are the highest-profile candidates and the only ones so far to report raising money.

Petersburg, where the challenger has lived for decades, is an island community of about 3,000 people in southeast Alaska that is accessible only by air or water. Many longtime residents find it hard to believe claims that their Dan Sullivan, a retired elementary and middle school teacher, is a dirty trickster.

“You really have to do a lot of mental gymnastics to suddenly not respect Dan Sullivan, because he’s honestly a very stand-up human being,” said Orin Pierson, publisher of the Petersburg Pilot newspaper.

Petersburg residents reflect and weigh their choices

Even some who do not know how they will vote, or declined to say, criticized the state’s attempts to block the political novice, saying he met the age, residency and citizenship requirements set out by the U.S. Constitution.

“To say somebody can’t run — that he’s fake — that’s fear,” said Linda Bunge, who attended a community potluck at a park where yellowish seaweed carpeted the beach at low tide. Bunge said she probably will vote for Peltola, a former congresswoman, but would consider Dan J. Sullivan.

Jeigh Stanton Gregor, a borough Assembly member who worked with him years ago at the local elementary school, said he was somewhat surprised Sullivan was running because people previously tried to recruit him for local offices. He called Sullivan’s character “unimpeachable.”

Stanton Gregor said he wants to see how the campaign plays out before deciding which candidate to support. Dan J. Sullivan’s concerns about healthcare costs resonate with him, but Stanton Gregor also has found the senator easy to work with and respects Peltola. A registered Democrat, Stanton Gregor said he generally votes for the person, not the party.

“Being a good human carries a lot of weight with me,” he said.

Sullivan regroups after successful court fight

Last month, Republican Lt. Gov. Nancy Dahlstrom, who oversees elections, announced an investigation into Dan J. Sullivan’s run. She cited “credible allegations” that he ran in coordination with another candidate and campaign in an effort to “manipulate voters.” The announcement came after a lawyer for the National Republican Senatorial Committee asserted that Dan J. Sullivan’s work with a consultant who has worked with Democrats was evidence of an attempt to confuse voters and “rig the election” for Peltola. It is an assertion that the Republican Senate campaign arm has continued to make.

Dan J. Sullivan argued the state had no legal basis to block his candidacy. He said the allegation he worked with Peltola was “entirely false” and that the prior work of a consultant was not a legitimate reason to investigate him. The state Democratic Party and campaign groups denied recruiting Dan J. Sullivan or having any affiliation with him. The director of the state Division of Elections, Carol Beecher, in disqualifying him, did not mention finding any evidence of coordination.

But she determined he had not filed a “good-faith candidacy.” She cited factors such as his lack of affiliation with the Republican Party before filing and having a campaign site similar in appearance to the senator’s.

A state court judge voided her decision, ruling it was not based on constitutional or legal requirements and that there was not enough evidence to support her conclusion that Dan J. Sullivan aimed to confuse voters. The state Supreme Court affirmed placing him on the ballot but left to the Division of Elections to figure out how to do that.

While the challenger sought to appear as Republican Dan J. Sullivan, he is listed as Daniel J. Sullivan Jr., with no party affiliation. The senator is listed as Republican Dan S. Sullivan and as “incumbent,” a title not included for other candidates seeking reelection.

Dan J. Sullivan said he does not think that is fair, but if the agency’s concern “is truly that I’m going to confuse people, then this certainly will be a way that people should not be confused.”

He acknowledges his name gives him an advantage over the 13 candidates with little to no name recognition or campaign support. He is now trying to figure how to make the most of the limelight and deal with the scrutiny. He plans to take steps to fundraise and may campaign in other communities and participate in forums. Sullivan has a Facebook page and a basic campaign website.

“I want something to change, and it’s my right to do that,” he said. “I could put up a yard sign; I could write letters. In this case, I thought, wow, this would reach a lot more people.”

Trump’s compensation fund was a motivation to run

There was not one issue that prompted the Petersburg Sullivan to run, but he said he had grown frustrated by a senator he sees as unresponsive to constituents. He also wanted the incumbent to join Alaska’s senior senator, Republican Lisa Murkowski, in speaking out against a compensation fund proposed by the Trump administration and the possibility rioters who stormed the U.S. Capitol on Jan. 6, 2021, could benefit from it.

Dan J. Sullivan said he worries President Donald Trump’s tariff policies and the war with Iran are driving up costs for Alaskans. He does not see the rural healthcare funding approved by Congress last year and promoted as transformational by the senator as helping address immediate needs.

Petersburg, like many small Alaska communities, has limited healthcare options. Residents needing specialized care must travel to larger cities. Residents will often maximize a trip to Juneau, the nearest city of size, by taking their vehicles on the state-run ferry and stocking up at Costco on cheaper groceries and supplies.

Resident Grace Wolf said she appreciates what the senator has done, saying he is fiscally responsible and that she likes his military background. The senator was a long-serving Marine and retired as a colonel in the Marine Corps Reserve. But “I feel like this time around, grassroots might be the way to go,” she said.

She plans to vote for Dan J. Sullivan, whom she knows as Mr. Sullivan.

Wolf worries about people being able to afford to stay in or move to the area and about protecting the health of local fisheries so important to the economy. Having people in office who can relate to those challenges is important, she said.

“I think we stand a better chance with having them at the helm and protecting our interests. It doesn’t matter if they’ve got a ‘D’ or an ‘R’ by their names. They’re our neighbors and they know what we’re going through.”