"The contrast Frankfurt draws between lying and bullshit is sharp. 'It is impossible for someone to lie unless he thinks he knows the truth,' Frankfurt observes. 'Producing bullshit requires no such conviction. A person who lies is thereby responding to the truth, and he is to that extent respectful of it. When an honest man speaks, he says only what he believes to be true; and for the liar, it is correspondingly indispensable that he considers his statements to be false. For the bullshitter, however, all bets are off. … He does not reject the authority of the truth, as the liar does, and oppose himself to it. He pays no attention to it at all. By virtue of this, bullshit is a greater enemy of truth than lies are.'
"Frankfurt's analysis works extraordinarily well in explaining why Trump is so unfazed when called on his bullshit."
In a 2015 New Republic article, Jeet Heer calls Donald Trump "a bullshit artist."
And Heer follows up on the subject in 2018.