> No matter how much he claims to.

Unless he makes a series of public orders that says he will install Apparatchiks in every independent agency and law enforcement agency for compliance, will (and does) fire anyone who goes against his will, then states that he is the sole arbiter of law for all law enforcement and military members.

Then he very much can have that authority if enough people comply. And, if you look around, it's pretty obvious the police and executive are complying.

State power has only gotten weaker and weaker compared to the federal government over time.