BOZEMAN (AP) — Republican multimillionaire Greg Gianforte won Montana’s only U.S. House seat on Thursday despite being charged a day earlier with assault after witnesses said he grabbed a reporter by the neck and threw him to the ground.

Gianforte, a technology entrepreneur, defeated Democrat Rob Quist to continue the GOP’s two-decade stronghold on the congressional seat. Democrats had hoped Quist, a musician and first-time candidate, could have capitalized on a wave of activism following President Donald Trump’s election.

Instead, the win reaffirmed Montana’s voters support for Trump’s young presidency in a conservative-leaning state that voted overwhelmingly for him in November.

Gianforte was a strong favorite throughout the campaign and that continued even after authorities charged him with misdemeanor assault on Wednesday. Witnesses said he grabbed Ben Jacobs, a reporter for the Guardian newspaper, and slammed him to the ground after being asked about the Republican health care bill.

Gianforte dropped out of sight after he was cited by police and ignored calls on Thursday by national Republicans for him to apologize to the reporter.

He emerged only at his victory celebration Thursday night, where he said he accepted responsibility for the incident. “Last night I made a mistake and I took an action I can’t take back and I am not proud of what happened,” Gianforte told the crowd. “I should not have responded the way I did and for that I am sorry.”

The last-minute controversy unnerved Republicans, who also faced close calls this year in the traditionally Republican congressional districts in Kansas and Georgia. A runoff election is scheduled for next month in Georgia between Democrat Jon Ossoff and Republican Karen Handel after Ossoff fell just short of winning outright.

Gianforte showed lukewarm support for Trump during his unsuccessful run for governor in Montana last fall but did an about-face and turned into an ebullient Trump supporter after he started campaigning for the congressional seat vacated by Republican Ryan Zinke, when he was tapped by Trump to serve as Interior Department secretary.

Gianforte urged Montana voters to send him to help Trump “drain the swamp,” brought in Vice President Mike Pence and first son Donald Trump Jr. to campaign for him and was supported by millions of dollars of ads and mailers paid for by Republican groups.

But the theme of the election shifted Wednesday night when Jacobs walked into Gianforte’s office as he was preparing for an interview with Fox News.

Jacobs began asking the candidate about the health care bill passed by the House when the crew and Jacobs say Gianforte slammed him to the floor, yelling “Get out of here!”

Gianforte’s campaign issued a statement Wednesday blaming the incident on Jacobs. But on Thursday night, Gianforte apologized both to Jacobs and to the Fox News crew for having to witness the attack. “I should not have treated that reporter that way and for that I’m sorry, Mr. Jacobs.”

The chairman of the Montana Republican Party, Rep. Jeff Essmann, said Thursday night that Gianforte “is a human being, and he acted like one” during Wednesday’s altercation.

Three of Montana’s biggest newspapers pulled their endorsements of Gianforte — without endorsing his opponent — while leaders of both major parties called on him to apologize.

House Speaker Paul Ryan, a Republican, said what occurred was “wrong and should not happen.” House Minority Leader Nancy Pelosi called Gianforte “a wannabe Trump.”

Gallatin County Sheriff Brian Gootkin said Gianforte was charged with a misdemeanor instead of a felony because no weapon was used and Jacobs was not seriously injured. The county prosecutor is reviewing the case.

If convicted, Gianforte could face up to six months in jail and a $500 fine.

It had been unclear if Gianforte’s assault charge would impact the race. About a third of eligible voters in Montana had already cast their ballots in early voting, and others said it didn’t influence their vote.

Quist, a popular 69-year-old singer and cowboy poet who was the front man for the Montana’s Mission Mountain Wood Band, was helped by money that poured in from across the U.S. as Democrats seek to capture congressional seats that would have been considered safely Republican a year ago.

But Gianforte also benefited from millions of dollars spent on ads and mailers by GOP groups like the Conservative Leadership Fund.

Gianforte campaigned as a gun-loving Montanan endorsed by the National Rifle Association to build his credibility among hunting enthusiasts and to motivate gun rights activists to vote. He echoed the Republican Party mantras of cutting taxes, beefing up the military and securing the country’s borders.

Montana is a conservative-leaning state that became even more so after voters last November overwhelmingly supported Trump, voted in Republican majorities in the state Legislature and elected GOP candidates to four of five statewide elected positions, leaving Gov. Steve Bullock as the only Democratic statewide elected official.

A Democrat has not held the Montana U.S. House seat since Pat Williams departed in 1997 after he decided not to seek re-election.

Quist ran a nontraditional populist campaign that saw appearances by Sen. Bernie Sanders of Vermont. He stuck to issues that have broad appeal in Montana, such as maintaining and improving access to public land. He collected nearly $3.2 million from individual donors across the U.S.

But Quist had to overcome reports of financial problems that included unpaid taxes, a loan default and legal squabbles with a former band member over royalties and a contractor over payments. He tried to turn those negatives into positives by saying his story illustrated problems many Montanans face because of high health care costs.

Libertarian Mark Wicks was the third candidate in the race.

Preliminary results as of Friday 12:17 a.m.:

Statewide

507 of 681 precincts

Greg Gianforte, GOP 186,110 - 51%

Rob Quist, Dem 158,860 - 43%

Mark Wicks, Lib 21,073 - 6%

Flathead County

42 of 42 precincts

Gianforte: 20,257 - 57.44%

Quist: 13,566 - 38.47%

Wicks: 1,444 - 4.09%

Lake County

20 of 20 precincts

Gianforte: 5,161 - 51.67%

Quist: 4,384 - 43.89%

Wicks: 444 - 4.44%

Lincoln County

14 of 14 precincts

Gianforte: 4,471 — 65.28%

Quist: 2,104 — 30.72%

Wicks: 260 — 3.8%

Mineral County

6 of 6 precincts

Gianforte: 907 - 58.74%

Quist: 538 - 34.84%

Wicks: 99 - 6.41%

Sanders County

27 of 27 precincts

Gianforte: 2,898 - 63%

Quist: 1,352 - 29%

Wicks: 295 - 6%

— Preliminary results as of presstime