"Fear and Loyalty: How Donald Trump Took Over the Republican Party"
Jonathan Martin and Maggie Haberman at The New York Times:
Interviews with current and former Republican lawmakers as well as party strategists, many of whom requested anonymity so as not to publicly cross the president, suggest that many elected officials are effectively faced with two choices. They can vote with their feet by retiring — and a remarkable 40 percent of Republican members of Congress have done so or have been defeated at the ballot box since Mr. Trump took office.
Wow, calling 40% "remarkable" is an understatement.
Fear and Loyalty: How Donald Trump Took Over the Republican Party (Published 2019)
The president demands complete fealty, and as the impeachment hearings showed, he has largely attained it. To cross him is to risk losing a future in the Republican Party.