Louisiana voters chose Saturday to send Republican state Treasurer John Kennedy to the U.S. Senate, filling the nation's last Senate seat and giving the GOP a 52-48 edge in the chamber when the new term begins in January.

Kennedy had always been the runoff election's front-runner in a state that overwhelmingly supported Donald Trump. He defeated Democrat Foster Campbell, a state utility regulator whose chances were seen as such a long-shot that national Democratic organizations offered little assistance to Campbell's campaign.

As he celebrated the victory, Kennedy said he represented change in Washington.

"I believe that our future can be better than our present, but not if we keep going in the direction the Washington insiders have taken us the last eight years," he said. "That's about to change, folks."

Voters also filled two open U.S. House seats Saturday, choosing Republican Clay Higgins, a former sheriff's captain known as the "Cajun John Wayne," in the 3rd District representing southwest and south central Louisiana and Republican state Rep. Mike Johnson in the 4th District covering northwest Louisiana.

Louisiana has an open primary system in which all candidates run against each other. In the contests for the open congressional seats, the November primary ballots were packed with contenders, so the top two vote-getters advanced to Saturday's runoff.

The Senate runoff drew national attention, with President-elect Trump and Vice President-elect Mike Pence each traveling to Louisiana to rally for Kennedy. The national GOP provided resources and staff to assist Kennedy's campaign, while national Democratic organizations largely abandoned Campbell, assuming an easy Republican win.

Though Campbell's chance appeared slim, donations had poured in from around the country, and several Hollywood celebrities championed his candidacy aiming to bolster resistance to the Trump presidency. Campbell said the support he received across the country was "phenomenal."

"We worked as hard as possible. We left no stone unturned," Campbell said in his concession speech. "I make no excuses. We did everything humanly possible."

The co-chair of the Republican National Committee, Sharon Day, described Kennedy's win as capping "a year of historic Republican wins up and down the ballot.

"With 52 seats in the U.S. Senate, we are excited for Republicans to confirm a conservative Supreme Court justice and begin working with President-elect Trump to pass an agenda of change for the American people," Day said in a statement.

Louisiana Gov. John Bel Edwards, a Democrat and ardent Campbell supporter, congratulated Kennedy and pledged to work with him to "deliver great things for the people of Louisiana."

The Senate seat was open because Republican David Vitter decided against running for a third term after losing the governor's race last year. Both men vying for the seat are well-known figures, involved in Louisiana politics for decades.

Kennedy, an Oxford-educated lawyer from south Louisiana, is in his fifth term as treasurer, a role in which he repeatedly drew headlines for his financial clashes with Louisiana's governors.

He sprinkled speeches with examples of government-financed contracts he considered outrageous, like money "to study the effects of Swedish massage on bunny rabbits." In the runoff, he ran a safe, TV-focused effort highlighting his support for Trump and his opposition to the federal health overhaul.

Campbell, a cattle farmer and former state senator from north Louisiana, is a populist who railed against "Big Oil," wanted to increase the minimum wage and talked openly about man-made climate change. He pledged that in Washington he wouldn't "be in anybody's shirt pocket."

He also ran as a Louisiana Democrat — strongly opposed to abortion and supportive of gun rights.

Kennedy hit Campbell for supporting Clinton. Campbell called Kennedy a flip-flopper during prior Senate bids, because the treasurer ran in 2004 as a liberal Democrat and the most recent two times as a conservative Republican.

In the 3rd District race, Higgins traded blistering attacks with his fellow Republican opponent, Scott Angelle, a member of the Public Service Commission and well-known public official for nearly 30 years.

Angelle had been the presumed front-runner. But Higgins — a local celebrity known for attention-grabbing Crime Stoppers videos he filmed when he was a sheriff's captain — capitalized on disenchantment with career politicians to defeat Angelle with only a fraction of his money and a bare-bones organization.

In the 4th District, Johnson defeated Democrat Marshall Jones in a competition that was less attack-laden.

Johnson focused on his work on conservative issues as a constitutional attorney and on his two years as a state lawmaker. Jones, also a lawyer, downplayed his party affiliation, running as an anti-abortion, gun-rights Democrat who could work with Trump.

The House seats were open because Republicans Charles Boustany and John Fleming unsuccessfully sought the Senate seat instead of re-election.