Hopes fading for senate control, Democrats had a disappointing election night as Republicans swatted down an onslaught of challengers and fought to retain their fragile majority. Several races remained undecided into Wednesday and at least one headed to a runoff in January.

It was a jarring outcome for Democrats who had devised an expanded political map, eager to provide a backstop against President Donald Trump and his party’s grip on the senate. The races attracted an unprecedented outpouring of small-dollar donations from Americans apparently voting with their pocketbooks to propel long-shot campaigns.

The voters’ choices will force a rethinking of Democratic Party strategy, messaging and approach from the Trump era.

While Democrats picked up must-win seats in Colorado and Arizona, they suffered a setback in Alabama, and Republicans held their own in one race after another — in South Carolina, Iowa, Texas, Kansas and Montana, dramatically limiting the places where Democrats hoped to make inroads.

“You wasted a lot of money,” said White House ally Sen Lindsey Graham in Columbia, South Carolina, after defeating Jamie Harrison, despite the Democrat’s stunning $100 million haul for his upstart campaign. “This is the worst return on investment in the history of American politics.”

Trump loomed large over the Senate races as did Democratic rival Joe Biden. The Trump administration’s handling of the Covid-19 crisis, its economic fallout and the nation’s uneasy mood all seemed to be on the ballot.

Voters ranked the pandemic and the economy as top concerns, according to AP VoteCast, a national survey of the electorate.

“It’s time for a different approach,” said Democrat John Hickenlooper, a former governor who unseated Republican Sen Cory Gardner in Colorado, during a live video message posted on Facebook.

Yet voters, for the most part, stuck with the status quo.

Securing the senate majority will be vital for the winner of the presidency. Senators confirm administration nominees, including the cabinet, and can propel or stall the White House agenda. With Republicans now controlling the chamber, 53-47, three or four seats will determine party control, depending on who wins the presidency because the vice president can break a tie in the senate.

Democrats contested seats from New England to the Deep South and the Midwest to the Mountain West, reaching deep into GOP strongholds. But by early Wednesday, the tally was not too different from before Election Day.

The Democrats’ gains were in Colorado and Arizona, where former astronaut Mark Kelly beat GOP incumbent Martha McSally. But they couldn’t hold on in Alabama: former college football coach Tommy Tuberville defeated Sen Doug Jones.

Several battlegrounds broke for Republicans: In South Carolina, Graham survived the race of his political career against Harrison; in Texas, Sen John Cornyn turned back former Air Force helicopter pilot MJ Hegar; in Iowa, Sen Joni Ernst defeated Democrat Theresa Greenfield in a race seen as a toss-up; in Montana, Sen Steve Daines routed Gov Steve Bullock; and in Kansas, Rep Roger Marshall prevailed over state Sen Barbara Bollier, a former Republican who energised Democrats in a state that hasn’t elected a Democrat to the Senate since 1932.

The final breakdown awaited the outcome of races in Alaska, Maine, Michigan, North Carolina and Maine.

Senate Majority Leader Mitch McConnell acknowledged the uncertainty still ahead even after he secured a seventh term in Kentucky, fending off Democrat Amy McGrath, a former fighter pilot in a costly campaign.

“We don’t know which party will control the senate,” McConnell said from Louisville. “But some things are certain already. We know grave challenges will remain before us, challenges that could not care less about our political polarisation. We know our next president will need to unite the country, even as we all continue to bring different ideas and commitments to the table.”

North Carolina Republican Sen Thom Tillis has struggled against Democrat Cal Cunningham, despite the married challenger’s sexting scandal with a public relations strategist.

And in Maine, the race between GOP Sen Susan Collins and Democrat Sara Gideon could be another one that pushes later into the week. If no one in the multi-candidate field breaks the 50 per cent threshold in the first-round votes, then there are additional tabulations in which last-place finishers are eliminated. Under the state’s rank-choice system the tabulations continue until a candidate achieves a majority.

In Georgia, two seats were being contested and at least one is headed to a runoff after no candidate reached the 50pc threshold to win.

GOP Sen Kelly Loeffler will face Democrat Raphael Warnock, a black pastor at the church where the Rev Martin Luther King Jr preached, in the Jan 5 runoff special election for the seat Loeffler was tapped to fill for retired Sen Johnny Isakson.

In the other, GOP Sen David Perdue, the former business executive Trump calls his favourite senator, tried to stave off Democrat Jon Ossoff, another candidate who has benefited from the “green wave” of campaign donations. It, too, could go to a runoff.

Republicans were on defence in most states. But in the presidential battleground of Michigan, Republicans made an aggressive push for John James, a black Republican businessman who stood by Trump at a rally late Monday, against Democratic Sen Gary Peters.

In South Carolina, Graham eventually caught up with Harrison’s fundraising as the Senate Judiciary Committee chairman led the confirmation of Trump’s Supreme Court nominee Amy Coney Barrett, sometimes making pleas for cash during appearances on TV.

Harrison energised voters, among several black candidates for senate including Warnock, drawing an outpouring of national support in a year of racial reckoning.

“We didn’t get the result at the ballot box that we wanted, but we showed courage and determination,” Harrison said on Twitter. “We brought hope back to South Carolina.”

Stuck in Washington as McConnell rushed the Senate to confirm Barrett a week before Election Day, senators quickly fanned out — some alongside the president — for last-ditch tours, often socially distanced in the pandemic, to shore up votes.

Democrats tried to win over voters promising to protect access to health care and provide a plan to reserve the Covid crisis. Republicans promoted their alliance with Trump, and their success in confirming conservative judicial nominees, including three to the Supreme Court.

The political landscape is quickly changing from six years ago when most of these senators last faced voters. It’s a reminder of how sharply the political climate has shifted in the Trump era. Or not.

In Alaska, newcomer Al Gross, a doctor, broke state fundraising records in part with viral campaign ads as he took on GOP Sen Dan Sullivan.

The senate will welcome some newcomers as others retire. In New Mexico, Democrat Ben Ray Lujan, a member of House leadership, was elected to the seat held by Democrat Tom Udall. Tennessee Republican Bill Hagerty won the seat held by Republican Lamar Alexander. Republican Cynthia Lummis, the former congresswoman from Wyoming, won the Senate seat being vacated by Republican Mike Enzi.