Flake. Corker. Romney. And now, Tillis. The list of Republican senators who have called it quits rather than endure a political career sideways with Trump is long and still growing.

Thom Tillis' surprise retirement announcement over the weekend creates a sudden opening in next year’s midterm elections, setting off a scramble of successor speculation that includes both a former Democratic governor and a Trump other than the one who ultimately nudged Tillis into leaving.

Senate Majority Leader John Thune said Tillis gave him a heads-up he would retire: “It’s unfortunate, and it’s something he’s been thinking about for a while and he just finally decided that was the best decision for him and his family,” he told POLITICO.