Tillis made the surprise announcement one day after he opposed a massive bill for Trump's agenda in the Senate.

"It's not a hard choice, and I will not be seeking re-election," Sen. Thom Tillis announced. His announcement comes after he voted against advancing President Donald Trump's megabill. Trump has repeatedly criticized Tillis over his opposition to the sweeping tax package — and has threatened to explore primary challengers to the two-term senator.

Republican Sen. Thom Tillis of North Carolina announced Sunday he is not seeking reelection next year, a day after he was one of only two Republicans who voted against advancing President Donald Trump’s sweeping agenda bill.