I agree with hoolies. I am increasingly convinced that Trump's tweets and statements are not a conspiracy from him, but a genuine incompetence and instability. He sees news, he reacts, he tweets. He lives completely in the moment. He says in speeches what he wants people to hear and then does what is easiest. So he said he would use American steel because he wanted the applause, he doesn't consider anything past that point. How he will deliver that doesn't even enter his head. When he is then sitting in a meeting with people buying the steel he will agree to what they say as in that moment he wants their adoration. Of course this trait can be used by people who do have ambitions and push him to agree what they want. It is a dangerous strategy though as people like this are incredibly erratic and just as likely to agree with the opposite of what you want.
I have had a manager just like this. She would sit in a meeting and agree whatever madness the other person wanted. She would then sit with me agreeing it was madness and we definitely would not do it. She would of course leave me to deal with the people who she had told would get whatever they wanted even though we could not possibly deliver it. She also, never, ever admitted she was wrong. 