Sen. Thom Tillis (R-NC) is finishing his final months in the Senate on an introspective note, revealing in a new book that the “biggest regret of my career” was his vote to confirm War Secretary Pete Hegseth.

In How to Lose Friends and Antagonize Presidents, Tillis describes the extent of his early reservations about President Donald Trump’s Cabinet, naming Hegseth but also Robert F. Kennedy Jr. and Tulsi Gabbard — his health secretary and ex-intelligence chief — as nominees he wished he opposed.