How many injuries to American democracy can my Republican Party tolerate, excuse and champion? It is elementary to have to say so, but for democracy to work one side must be prepared to accept defeat. If the only acceptable outcome is for your side to win, and a loser simply refuses to lose, then America is imperiled.

I once had a career in public life — six terms in the House of Representatives and another six years in the Senate — and then the rise of a dangerous demagogue, and my party’s embrace of him, ended that career. Or rather, I chose not to go along with my party’s rejection of its core conservative principles in favor of that demagogue. In a speech on the Senate floor on Oct. 24, 2017, I announced that because of the turn my party had taken, I would not run for re-election: the career of a politician that is complicit in undermining his own values doesn’t mean much.

As a lifelong conservative Republican, I was surprised to find myself so profoundly at odds with my own party and with the man who had used its ballot line to vault to power. But the values that made me a conservative and an American were indeed being undermined, the country was paying a steep price for it, and I would be a liar to my family, my state and my conscience if I were to pretend otherwise.