BILLINGS — Montana Democrat Jon Tester captured a third term in the U.S. Senate with an extremely narrow victory over an opponent President Donald Trump tried to boost by making repeated visits to the state.

Tester’s re-election over State Auditor Matt Rosendale helps stem Republican gains elsewhere in the nation that allowed the GOP to keep an edge in the Senate even as it lost control of the House.

During a victory speech Wednesday before supporters in Great Falls, Tester lamented the negative tone of a race that often turned personal. He pledged cooperation across the aisle when the new Congress convenes.

“We need to put aside the political pettiness and work together,” Tester said. “Whether it’s public lands or health care, veterans care or making sure we have government accountability and a transparent government. ... These are bipartisan issues. Let’s get ‘er done.”

Rosendale conceded defeat and called Tester to congratulate him soon after The Associated Press called the race Wednesday.

“While we suffered a setback, our movement and our cause will continue to move forward,” Rosendale said. “As your state auditor, I will continue to fight for you in Helena to lower health care costs and expand options and hold the line on government spending.”

The president vowed last spring that Tester would pay at the polls for sinking his first nominee for Veterans Affairs secretary, White House physician Ronny Jackson. Those comments led to both Republican and Democratic groups spending tens of millions of dollars in an attempt to influence the outcome of the race.

Tester insisted that Montana voters across the political spectrum would support him after examining his record. He has never won a U.S. Senate election with a majority of the vote, and he said he knew it would be close again this time. His seat was one of 10 held by Senate Democrats seeking re-election in states Trump won in 2016.

Tester sought to capitalize on a Democratic base outraged by Trump’s election and energized by the #MeToo movement against sexual misconduct. At the same time, he tried to appeal to the Trump supporters he needed to win. He cast himself as an independent who would support the president when it was in Montana’s interests and oppose him when it wasn’t.

Tester repeatedly cited legislation that he helped draft and that Trump signed as evidence he can work with the administration. He said his opposition to Trump’s Supreme Court picks, Brett Kavanaugh and Neil Gorsuch, were examples of when he had to go against the president.

Tester, 62, is a farmer and a former music teacher from the small community of Big Sandy who previously served in the Montana Legislature. He won his seat in 2006 by defeating then-U.S. Sen. Conrad Burns. Six years later, Tester beat then-U.S. Rep. Denny Rehberg in his first re-election campaign.

Rosendale, 58, was elected state auditor in 2016 and is a former Senate majority leader in the Montana Legislature, where he represented the Glendive area from 2011 to 2017.

He is a real estate developer originally from Maryland who has lived in Montana since 2002. He previously ran for the U.S. House in 2014, where he came in third in the Republican primary and achieved notoriety for an ad in which he pretended to shoot a government drone from the sky with a rifle.

He won a four-way primary in June after the Republicans’ first choice to challenge Tester, Ryan Zinke, resigned his U.S. House seat to become Trump’s Interior Department secretary last year.

Rosendale made his campaign about backing Trump, who won a landslide victory in Montana in 2016. Rosendale framed himself as a champion of the president’s agenda and Tester as selling out Montana’s interests for those of the Senate’s Democratic leaders.

The race tightened as Trump, eldest son Donald Trump Jr. and Vice President Mike Pence made repeated trips to Montana to rally for Rosendale. The president visited four times after saying Tester would have to pay for Jackson withdrawing his name from consideration as head of the VA amid allegations of workplace misconduct.

Trump blamed Tester, the ranking member of the committee that oversees the VA, for releasing excerpts from interviews with unnamed people who said Jackson drank on the job, overprescribed medication and presided over a toxic work environment.