WATERVILLE — For the first time since she won a U.S. Senate seat in 1996, Maine Republican Susan Collins is likely to face a challenge next year from within the ranks of the GOP.

Derek Levasseur, 44, who runs a small construction company in Fairfield, said Tuesday that Collins has lost touch with ordinary Mainers and will have a tough time convincing Republicans in a primary she deserves a fifth term in Washington.

The challenger, who filed this week as a candidate with the Federal Election Commission, said Collins is “a great person” but has forgotten the constitutional values ordinary Mainers hold dear.

Calling himself “a common man with common sense,” Levasseur said Collins has not stood by President Donald Trump on key issues, such as border security and gun rights.

During an interview at a Best Western hotel before a campaign staff meeting, Levasseur said he has a popular blog and a growing base of support that he insists has Collins worried. She ought to be concerned, he said.

“Who is she trying to represent? Not Republicans!” he wrote on Facebook recently. “It is time to fight for conservative values!”

Collins has not officially declared her 2020 candidacy, but she is raising money at a record clip. By the end of March, she had raised $3.8 million for her campaign, most of it from big, out-of-state donors.

The only Republican challenger she has faced since her first election as senator was a low-key, write-in effort in 2014 by conservative Erick Bennett, a Portland political consultant. She easily swatted him away.

But Levasseur, who serves on the Republican State Committee, is raising money, rounding up volunteers and insisted he will appear on the June 2020 primary ballot as a serious contender for his party’s backing.

Though some on the right and left have expressed concern about Collins, she appears to be holding her own among Maine voters.

Pan Atlantic Research of Portland’s annual spring poll found 62% of Mainers have a very or somewhat favorable view of her, compared to 37% who do not.

A quarter of Maine voters said they would definitely support Collins in her re-election bid, and another 40% said they would consider voting for her.

The results, though, do not give any indication of how Maine’s senior senator stands among her own party’s ranks. Levasseur said he thinks she has slipped badly because she has avoided town halls, refused to endorse Trump and failed to keep her promise to serve only two six-year terms.

Collins did not support Trump in the 2016 election, and has not said whether she will back him next year. She is pro-choice and has questioned some of the president’s immigration and border policies.

Levasseur said he opposes abortion but generally shares many of Collins’ views on social issues.

Levasseur, who is married and has two adult children and two younger ones from a second marriage, said he is counting on his passion and his love of people to forge a coalition that can win the primary and then defeat the Democrats’ candidate.

There is only one Democrat active in the race so far: Saco lawyer Bre Kidman. But several more prominent Democrats are weighing whether to run, including ex-Lewiston Mayor James Howaniec and House Speaker Sara Gideon of Freeport.

Levasseur said it is crucial the person who fills the Senate seat now held by Collins offers strong support for the economic agenda Trump has put forth. Levasseur credits the president with creating a booming economy that has provided so many jobs that “right now it’s hard to find employees.”

Levasseur said he is also happy Trump has given strong support to the military.

“We want to look strong,” Levasseur said, so adversaries will not mess with the United States.

Before he got into construction with his brother, Levasseur had a three-year career in law enforcement. Initially hired in 2009 as a deputy with the Kennebec County Sheriff’s Office, he resigned and in 2012 became a part-time, reserve officer with the Clinton Police Department.

That came to an end later in 2012, when police arrested him following a 1 a.m. altercation at his own wedding on a misdemeanor charge of domestic violence assault — against his 15-year-old daughter — and four counts of misdemeanor assault, reported at the time in the Morning Sentinel.

As part of his bail conditions, he was barred from contacting his daughter, possessing a gun or consuming drugs or alcohol.

“I believed I was doing the right thing in protecting my daughter,” Levasseur said in a Facebook post recently. “Charges did follow the incident, but I was able to have my day in court.”

He said he was ultimately found not guilty. The charges have been expunged from his record.

Levasseur said Tuesday the incident occurred long ago and he hopes, for his daughter’s sake, his one-time mistake will not become an issue on the campaign trail.

He said he liked serving in the police but recognizes now how much trauma he saw, from suicides to car wrecks, and believes government ought to do more to help public safety personnel who suffer from post-traumatic stress.

One incident that has stuck with him, though, had a happier outcome. He said he once responded to a woman who had stopped breathing. He worked to resuscitate her for at least 8 minutes, fearing she would not make it.

When medical personnel arrived and managed to get her heart beating again, he realized as he watched the monitor showing each heartbeat how precious and fragile life can be. This experience turned him against abortion, he said, because he sees a duty in trying to keep every heart beating.

Levasseur said he is not a conventional right-winger, although he agrees government is too intrusive and costs too much.

He said he wants government to do more for retirees and veterans who too often struggle to make ends meet on the aid they receive after a lifetime of work.

Levasseur said the country also has to do more to tackle mental health issues.

He said he is tired of seeing politicians from both parties sniping at one another instead of trying to address the nation’s needs.

“We need people who are going to look out for the common people,” Levasseur said.

The challenger said he does not have any intention of bashing Collins or anyone else. He said he has met the senator and talked with her before.

“She’s a great person,” Levasseur said.

But she has been on Capitol Hill too long, he said, and has never really experienced the ups and downs ordinary Mainers face in their lives.

He said his basic message to Collins is straightforward: “Do your job or get fired.”