Rep. Adam Kinzinger (R-Ill.), one of only 10 House Republicans who voted to impeach then-President Donald Trump this year, recently told the Atlantic why he remains committed to the party: “I’m a Republican because I’ve been a Republican far longer than Donald Trump has. He’s a Republican usurper.… I’m not going to let him take the party. So I will fight. I will fight like hell.” It is a decision I have not for a moment regretted, because the GOP has become even more of a horror show than I anticipated. As former House speaker John Boehner (R-Ohio) notes in...