Republicans have retaken the U.S. Senate, achieving what was touted as the party's most achievable goal in this year's election.

The GOP regained control after it became clear that Democrats had lost their one-seat majority in the 100-member upper house of Congress.

Republicans gained two Senate seats as Trump-backed businessman Bernie Moreno defeated three-term Democratic Sen. Sherrod Brown in Ohio and Trump loyalist Jim Justice won the seat once held by Joe Manchin in West Virginia.

Republican incumbents also battled Democratic challengers in Texas, where Ted Cruz defeated Collin Allred, and in Florida, where Rick Scott defeated Debbie Mucarsel-Powell.

In Nebraska, union organizer Dan Osborn launched a surprisingly successful independent campaign to oust Republican incumbent Deb Fisher. But ultimately Fisher kept her seat.

Shortly after midnight ET, several competitive Senate races were still not scheduled, giving Republicans a chance to increase their majority by a few more seats.

The result puts the Republican Party at the top of the confirmation process for senior officials appointed by the incoming new administration and for potential new justices on the U.S. Supreme Court if vacancies become available.

At least two veteran conservative justices, Clarence Thomas and Samuel Alito, are expected to retire in the next few years, while there is speculation about the health and intentions of a third, Sonia Sotomayor, one of the court's three liberal justices.

The transfer of Senate control back to Republicans will also add even more heat to the race to replace Mitch McConnell, the GOP leader in the House of Representatives who has said he will retire after the election.

The main contenders to replace him include John Thune of South Dakota, Texas Sen. John Cornyn and Rick Scott of Florida, with the winner primed to assume the powerful position of Senate majority leader.

According to the Associated Press, Cornyn launched his leadership bid just moments after Republicans won their Senate majority with a statement highlighting his experiences working with Republican members and as a GOP vote counter during the first Trump administration.

“As I’ve said before, this election is not about us, it’s about what’s best for the conference and the nation,” the Texas Republican said. “I look forward to working with President Trump and our new conservative majority to Make America Great Again by getting the Senate functioning again.”

The leadership election is scheduled to take place at the end of November in a secret vote.

The Republican victory had been widely expected as the party needed to make a net gain of just one seat to regain control if Donald Trump took back the White House, since – constitutionally – the vice president is entitled to the tie-breaking vote if both parties do so bound.

But Democrats also faced an adverse electoral situation, with several incumbents in Republican strongholds either retiring or running for re-election – meaning a loss of control of the Senate even if Kamala Harris were elected President would very likely be.

The resignation of West Virginia Senator Joe Manchin, a former centrist Democrat who had recently become an independent, was the clearest signal that Republicans were on a winning path. As expected, the seat he vacated was won by the state's Republican governor, Jim Justice, who triumphed over his Democratic opponent Glenn Elliott, the mayor of Wheeling.

Read more of the Guardian's coverage of the 2024 US election