His decision creates a political opportunity for Democrats seeking to bolster their numbers in the 2026 midterm elections, creating a wide-open Senate race in a state that has long been a contested battleground. It could also make Tillis a wild card in a party where few lawmakers are willing to risk Trump’s wrath by opposing his agenda or actions. Trump had already been threatening him with a primary challenge.

“In Washington over the last few years, it’s become increasingly evident that leaders who are willing to embrace bipartisanship, compromise, and demonstrate independent thinking are becoming an endangered species,” Tillis said in a lengthy statement.

Tillis, who would have been up for a third term, said he was proud of his career in public service but acknowledged the difficult political environment for those who buck their party and go it alone.

“I look forward to having the pure freedom to call the balls and strikes as I see fit and representing the great people of North Carolina to the best of my ability,” Tillis said in a statement.

Republicans hold a 53-47 edge in the Senate.

Trump, in social posts, had berated Tillis for being one of two Republican senators who voted on Saturday night against advancing the massive tax bill.

The Republican president accused Tillis of seeking publicity with his “no” vote and threatened to campaign against him, accusing the senator of doing nothing to help his constituents after last year’s devastating floods in western North Carolina from Hurricane Helene.

“Tillis is a talker and complainer, NOT A DOER,” Trump wrote.

The North Carolina Republican Party chairman, Jason Simmons, said the party wishes Tillis well and “will hold this seat for Republicans in 2026.” Sen. Tim Scott of South Carolina, the chairman of the campaign arm for Senate Republicans, did not mention Tillis in a statement but said the party’s winning streak in North Carolina will continue. Scott noted that Trump won the state three times.

Democrats expressed confidence about their prospects.

Former Rep. Wiley Nickel, who announced his candidacy in April, said he was ready for any Republican challenger.

“I’ve flipped a tough seat before and we’re going to do it again,” Nickel said in a statement.

Some said Tillis’ decision is another sign of the dramatic transformation of the Republican Party under Trump, with few lawmakers critical of the president or his agenda remaining in office.

It “proves there is no space within the Republican Party to dissent over taking health care away from 11.8 million people,” said Lauren French, spokesperson for the Senate Majority PAC, a political committee aligned with the chamber’s Democratic members.

Tillis rose to prominence in North Carolina when, as a second-term state House member, he quit his IBM consultant job and led the GOP’s recruitment and fundraising efforts in the chamber for the 2010 elections. Republicans won majorities in the House and Senate for the first time in 140 years.

Tillis was later elected as state House speaker and helped enact conservative policies on taxes, gun rights, regulations and abortion while serving in the role for four years. He also helped push a state constitutional referendum to ban gay marriage, which was approved by voters in 2012 but was ultimately struck down by the courts as unconstitutional.

In 2014, Tillis helped flip control of the U.S. Senate to the GOP after narrowly defeating Democratic Sen. Kay Hagan. During his more than a decade in office, he championed issues such as mental health and substance abuse recovery, Medicaid expansion and support for veterans.

As a more moderate Republican, Tillis became known for his willingness to work across the aisle on some issues. That got him into trouble with his party at times, most notably in 2023 when North Carolina Republicans voted to censure him over several matters, including his challenges to certain immigration policies and his gun policy record.

“Sometimes those bipartisan initiatives got me into trouble with my own party,” Tillis said, “but I wouldn’t have changed a single one.”