One of Mr Trump's many issues is that he lacks the mental agility essential to politicians - remembering what you have said when a camera and / or a microphone was near your face, which as a presidential candidate, is now always.
Mr Trump is probably used to jawing away in his boardrooms, changing his mind at will, and contradicting himself on every day with a 'y' in it.
That's fine for business, - it's even fine for a reality TV show with editing facilities. But on the barbed wire treadmill of politics, he is failing with increasing regularity.