Rejection of democratic rules of the game
Denial of the legitimacy of political opponents
Toleration or encouragement of violence
Readiness to curtail civil liberties of political opponents.
The authors, writing in 2018, were able to give examples from
Donald Trump’s behavior in each of these areas. For example, in his 2016 campaign he repeatedly said the vote would be fraudulent. During the campaign he challenged
Hillary Clinton’s legitimacy and said she should be in jail. During his rallies, he encouraged his supporters to beat up protestors. And he threatened the media that had the audacity to criticize him.
Since that book was published, Trump has continued to engage in authoritarian behavior. Most notable were his attempt to become president for life by claiming that the election was full of fraud and his encouragement and continued defense of the January riot aimed at reversing the election.