HELENA, Mont. (AP) — An attorney on Monday announced a bid to unseat newly elected U.S. Rep. Greg Gianforte in next year's midterm race, becoming the first Democrat to establish a campaign committee to take on the Republican who attacked a reporter the day before a special election.

John Heenan of Billings, who is making his first bid for elected office, said he would use his experience as a consumer protection lawyer to advocate for Montana residents, including working to increase access to "quality, affordable health care."

National Democrats are expected to target Gianforte in the midterm election and are sure to remind voters that he pleaded guilty to a misdemeanor charge of assaulting a reporter for the Guardian newspaper. The attack got widespread attention, but Gianforte prevailed over his Democratic opponent by 6 percentage points.

It remains to be seen if Democrats can field a candidate who can help the party wrest control of a seat that has been in Republican hands for two decades.

Gianforte announced shortly after winning the May 25 special election that he would seek a second term as Montana's sole representative in the U.S. House.

"Greg remains focused on being a strong voice for Montana and Montanans' way of life," his spokesman, Travis Hall, said in an email.

Heenan said in an interview that he decided to run because of the attack on the reporter, who said he was body-slammed by Gianforte after trying to ask him questions about federal health care legislation.

"Frankly, the special election and Mr. Gianforte's assault on a reporter kind of started this," he said.

In an announcement emailed to reporters, Heenan used the vernacular of Sen. Bernie Sanders of Vermont and Sen. Elizabeth Warren of Massachusetts, stalwarts of the political left, in railing against the "rich and powerful" who "have been waging war on the middle class for many years now."

Heenan was among the team assembled by the commissioner of political practices last year to prosecute former state Rep. Art Wittich, a Republican from Bozeman, for campaign finance violations.

While he railed against the big money necessary to win public office, including candidates who have the ability to dig into deep pockets, Heenan said he was fully prepared to appeal for campaign cash.

He said he has been in conversations with Montana Democratic Party officials in recent weeks to inform them of his intentions. He lent himself $100,000, he said, to help launch his campaign.