1. The President of the United States is constitutionally head of the Executive Branch of the tri-partite federal government of the US. He is ALSO Commander in Chief of the Armed Forces of the United States. He/she is not Commander in Chief of the United States. That means that he is not king or emperor. Citizens of the US are not in any way obligated to accept his policy views. Only members of the armed forces are so obliged. The press idiots cannot absorb that idea. I am thinking of Maria Bartiromo who seems to yearn for Il Duce. The governors of the states ARE NOT the subordinates in any way of the president. Trump's nonsense implying that if they don't do what he likes he will remove them is without factual basis. The only way he could do that is to declare that state government had collapsed and declare martial law. He would personally be responsible for that in federal court after the crisis. He can, of course, seek to influence them using federal money as "bribes."
2. OTOH As Commander in Chief of the Armed Forces he can order those forces into action subject to subsequent action by Congress against him under the War Powers Act. A stupid woman reporter at today's WH briefing repeatedly asked him what the Rules of Engagement (ROE) are for the Navy in the Arabian Gulf in regard to Iranian harassment of our warships in those waters. Idiot! If the Commander in Chief says he has directed the US Navy to "shoot down and sink" Iranian vessels harassing our warships, that IS the ROE. pl