> Given that the executive branch implements the law, this would imply that the president's interpretation is all that matters. The other two branches have no real role left to play.

What role did the other two branches of government ever have in the executive branch? You're describing the normal state of affairs as if it were a shocking escalation. Actually, it's any deviation from this that is a constitutional problem. The elected president is the head of the executive branch. If he is not the head, then the executive branch has no connection to any democratic process at all. Who is a bureaucrat serving if not the president? An inner sense of fairness or fashion?