It may appear that Trump has the ability to preserve some sense of credibility in his words even though we all know he is an habitual liar. It may also appear that in the fog that his constant lying creates and sustains, his lies are being taken as the truth by his supporters and laughed at by others who know better, but there are also those that exist between the two and those are the ones that allow Trump to get away with so much shit that it looks as if he is actually for the most part believable.
His words do carry the weight of the office he holds and that may be why some folks tend to believe him or at least want to believe him out a false sense of patriotism or some other round-about rationale being put in play.
Point being, Trump has this habit of skipping the reasoning processes we all possess to some degree or another where whatever comes to his mind will instantly come out of his mouth no forethought involved at all. Then the inevitable backtracking and walk-backs have to be employed by his surrogates with Trump stubbornly sticking to what he originally said in his attempt to preserve some sense of awareness, knowledge and validity of his ramblings. Repeat ad nauseum.
He reminds me of those many authoritarians high and low that I've had to deal with who believe their status allows them to shout down any and all objections and/or counterpoints that disagree or disprove their words or actions. Invariably, these guys end up making fools of themselves.
However, the image they see themselves as will allow them to ignore the damage they've caused themselves as they've convinced themselves they are so high in authority as to make them immune from their own words and actions.
I've seen this firsthand too many times for it to be coincidental.
Trump is a classic case and also a barrier breaker in this regard.