Because the talking heads on TV told him to, and a lifetime of experience tells him not to trust his own judgement.What I cannot understand is that people like you hate him, in spite of all of his efforts to protect and improve your way of life. All of the people that you'd vote for are all for open borders. Look at what's going on at our Southern border. YOU are being replaced, pure and simple. But yet, in spite of the overwhelming evidence, you still don't get it.
Ask any Trump hater if they can find a single instance of him being called a racist before he ran against Hillary.
If there is any evidence of "Russian collusion" other than a dossier that was a creation of the Hillary campaign.
Watch them vapor lock.