Sarasota, a federal court ruled that the dismissal of Cox was illegal because the regulation that allowed Cox's appointment required that dismissal required gross impropriety.  And you're wrong.  The president can commit obstruction of justice, especially when the obstruction affects an investigation into potential illegal actions by him.  Your attempted analogy with DACA is specious.  Federal immigration law provides significant leeway for the AG, the director of immigration, or their designates to review individual cases and grant temporary residency.  That is what DACA was based on.  Finally, Sarasota the president is not a king.  He is the chief executive of the government.  He is required to obey all the laws and regulations of the country.  To believe otherwise is to believe the Constitution is simply a piece of paper.