Control of Congress was hanging in the balance, with both parties notching victories in some of the most competitive races in a midterm election focused on voter frustration over high inflation and the sudden rollback of abortion rights.
Democrats held a crucial Senate seat in New Hampshire, where incumbent Maggie Hassan defeated Republican Don Bolduc.
Mr Bolduc is a retired army general who initially promoted former president Donald Trump’s lies about the 2020 election but tried to shift away from some of the more extreme positions he took during the GOP primary. Republicans held Senate seats in Ohio and North Carolina.
A district-by-district fight was underway for control of the House, where Democrats held closely watched seats in moderate suburban districts from Virginia to Kansas and Rhode Island.
Representative Elaine Luria, a navy veteran who serves on the House committee investigating the January 6 insurrection, was the first Democratic incumbent to lose a highly competitive House district.
Many of the districts that could determine House control in states like New York and California had not been called.
The outcome of races for House and Senate will determine the future of President Joe Biden’s agenda and serve as a referendum on his administration as the nation reels from record-high inflation and concerns over the direction of the country.
Republican control of the House would likely trigger a round of investigations into Mr Biden and his family, while a GOP Senate takeover would hobble the president’s ability to make judicial appointments.
Democrats were facing historic headwinds. The party in power almost always suffers losses in the president’s first midterm elections, but Democrats had been hoping that anger from the Supreme Court’s decision to gut abortion rights might energise their voters to buck historical trends.
Florida Governor Ron DeSantis and his Texas counterpart Greg Abbott, two future possible Republican presidential contenders, beat back Democratic challengers to win re-election in the nation’s two largest red states.
For Democrat Beto O’Rourke, who lost to Mr Abbott, it was his third failed campaign since 2018.
In Georgia, Democratic Senator Raphael Warnock and Republican challenger Herschel Walker were vying for a seat that could determine control of the Senate.
Republicans have bet that messaging focused on the economy, gas prices and crime would resonate with voters at a time of soaring inflation and rising violence.
AP VoteCast, a broad survey of the national electorate, showed that high inflation and concerns about the fragility of democracy were heavily influencing voters.
Half of voters said inflation factored significantly, with groceries, fuel, housing, food and other costs that have shot up in the past year. Slightly fewer — 44% — said the future of democracy was their primary consideration.
Overall, 7 in 10 voters said the ruling overturning the 1973 decision enshrining abortion rights was an important factor in their midterm decisions.
VoteCast also showed the reversal was broadly unpopular.
About 6 in 10 say they are angry or dissatisfied by it, while about 4 in 10 were pleased. And roughly 6 in 10 say they favour a law guaranteeing access to legal abortion nationwide.
There were no widespread problems with ballots or voter intimidation reported around the country, though there were hiccups typical of most election days.