Washington — Democrat Roy Cooper defeated Michael Whatley in the North Carolina Senate race, CBS News projects, marking a flip for Democrats after GOP Sen. Thom Tillis opted not to seek reelection.

Cooper, 69, is a popular two-term governor and the longest-serving state attorney general in North Carolina’s history. His Senate candidacy set up North Carolina as Democrats’ best chance to win a Republican-held seat during the 2026 midterm elections.

Cooper faced off against Whatley, the former Republican National Committee chairman who had never previously run for office but was backed by President Trump.

Whatley, 57, worked in former President George W. Bush’s administration and as chief of staff for former North Carolina Sen. Elizabeth Dole before serving as chairman of the state Republican Party. He went on to play a central role in President Trump’s reelection effort as RNC chair, and entered the Senate race with the president’s encouragement.

North Carolina hasn’t elected a Democratic senator since 2008. And even before Tillis decided not to seek reelection, facing a primary threat from the president, the race was expected to be competitive, since Mr. Trump won the state by just three points in 2024.

While Whatley campaigned on helping enact Mr. Trump’s agenda and fighting for conservative values, Cooper leaned into the economy, with a “make stuff cost less” message. And amid the president’s unpopular war with Iran and high gas prices, Whatley’s closeness to the president did not appear to help the GOP’s chances in the Tar Heel State.

The projected victory for Cooper comes as Republicans are fighting to hang on to control of the upper chamber, after competitive races opened up in several states that Mr. Trump comfortably won in 2024. Democrats need to flip four seats, and defend a handful of others.