Congress passes an Energy Conservation Act. The act requires all users of energy in this country to reduce their consumption by a specified percentage, to be set by a presidential executive order. The act sets forth specific standards the President must use in setting the percentage and detailed procedures to be followed. The provision that allows the President to set the exact percentage is probably
constitutional, because it creates a limited administrative power to implement the statute.  constitutional, because inherent executive powers permit such action even without statutory authorization.  unconstitutional as an undue delegation of legislative power to the executive. unconstitutional, because it violates the due process clause of the Fifth Amendment.