Washington (AFP) - Republican hopes of a “red wave” carrying them to power in the US Congress faded Wednesday as Joe Biden’s Democrats put up a stronger-than-expected defense in a midterm contest headed for a cliff-hanger finish.

With a majority of Tuesday’s races called, Republicans seemed on track to reclaim the House of Representatives for the first time since 2018, but the Senate was still in play, with forecasts tentatively leaning Democratic.

And the midterms delivered a decidedly mixed bag for Donald Trump, who though not on the ballot loomed large over the contest, teasing a 2024 run and airing unsubstantiated allegations of Election Day fraud.

While the night saw wins by more than 100 Republicans embracing Trump’s “Big Lie” that Biden stole the 2020 election, several high-profile, election-denying acolytes of the former president came up short.

Aiming to deliver a rebuke of Biden’s presidency, against a backdrop of sky-high inflation and bitter culture wars, Republicans needed one extra seat to wrest control of the evenly divided Senate.

But by early Wednesday the only seat to change party hands went to the Democrats, with John Fetterman, a burly champion of progressive economic policies, triumphing in Pennsylvania.

In the House, early results suggested Republicans were on track for a majority – but only by a handful of seats, a far cry from their predictions.

Top Republican Kevin McCarthy – who hopes to be the lower chamber’s next speaker – struck an upbeat note, telling supporters in the early hours: “It is clear that we are going to take the House back.”

But Senator Lindsey Graham, a top Trump ally, bluntly conceded to NBC that the election is “definitely not a Republican wave, that’s for darn sure.”

- Four key races -

The president’s party has traditionally lost seats in midterm elections, and with Biden’s ratings stuck in the low 40s and Republicans pounding him over inflation and crime, pundits had predicted a drubbing.

That would have raised tough questions on whether America’s oldest-ever commander in chief, who turns 80 this month, should run again.

Instead Biden stands to emerge in much better shape than either of his Democratic predecessors, Barack Obama or Bill Clinton, who both took a hammering at the midterms.

Control of the Senate hinged early Wednesday on four key races that were still on a knife-edge.

Democrats need two more wins to successfully hold the chamber, while Republicans need three to flip it.

In Arizona, Nevada and Wisconsin, counting the remaining votes for Senate could take days. And Georgia may well go to a runoff scheduled for December 6.

- Florida swings right -

On a night of close contests, one of the most decisive wins was for rising Republican star Ron DeSantis, who won the gubernatorial race overwhelmingly in Florida, cementing his status as a top potential White House candidate in 2024.

DeSantis, who has railed against Covid-19 mitigation measures and transgender rights, was projected to have won by nearly 20 points against a folksy ex-governor, four years after squeaking by in his longtime swing state.

“We will never, ever surrender to the woke mob,” DeSantis told a victory party, using a derisive term for social justice campaigners.

But if the 44-year-old views his victory as a presidential mandate, he will likely face a stiff challenge from another Florida resident – Trump, who has teased an “exciting” announcement on November 15.

Among other races, Maura Healey will make history as the first openly lesbian governor in the United States, and in New York, where recent polls unnerved Democrats, Governor Kathy Hochul fended off a Republican challenge.

- Trump alleges fraud -

Trump, who faces criminal probes over taking top secret documents from the White House and trying to overturn the 2020 election, returned to his playbook of airing unsubstantiated claims of fraud.

In Arizona, Trump and his chosen candidate for governor, Kari Lake, alleged irregularities after problems with voting machines.

Officials in the most populous county of Maricopa said about 20 percent of the 223 polling stations experienced difficulties related to printers but that no one was denied the right to vote.

Biden has warned that Republicans pose a dire threat to democracy, calling out their growing embrace of voter conspiracy theories that fueled last year’s storming of the Capitol.

In the run-up to the election, an intruder espousing far-right beliefs broke into the San Francisco home of House Speaker Nancy Pelosi and bludgeoned her husband with a hammer.

Voting in Phoenix, Kenneth Bellows, a 32-year-old law student, said runaway inflation is “hurting Americans who are just trying to get by.”

“We don’t need any of the crazy woke rhetoric that’s going on right now. What we really need is focusing on everyday kitchen-table politics, to make sure taxes are low,” he said.

But at a restaurant serving up soul food in Pittsburgh, Lasaine Latimore, 77, said Democrats were best placed to help Americans.

“I just want my medical insurance and more money for dental and glasses,” she said.

A Republican victory could derail Biden’s legislative agenda, with Congress scuttling his ambitions on climate change and scrutinizing the billions of US dollars to help Ukraine fight Russia.