If the US President can murder a US Citizen then he obviously has great king-like power. The president is at the seat of power which executes justice, and the Supreme Court has ruled that he is therefore above the law, just as a king is. If he breaks some law in actions, it doesn't matter. Since he himself is responsible for enforcing the law, the laws do not apply to him.
But does that insulate the president from impeachment? There is the notion that you can't (or, at least, shouldn't) enforce the law by breaking the law.
I know that impeachment isn't likely this term, but we do have the mid-term elections before too long, and party leadership has been known to flip during those elections.
The President is the country's Commander in Chief, and is an executor of justice above the law, very similar to the role of a medieval king. The courts can make laws, but they don't apply to him. The courts are therefore inferior entities meant for normal citizens, not the President who is superior.
The courts don't make laws at all. They interpret laws to determine if they are valid and if they apply to individual cases. Congress makes the laws and the executive branch enforces those laws.
You guys will have a tough time doing anything against Donald Trump, so it's probably best to quit whining about it.
Well, we can always hope that he dies peacefully in his sleep before too long.