The logical flaw of signing statements

If the Administration can choose how to interpret a law through issuing signing statements, there's no difference between this and the power to ignore existing laws that were in place before the President came into office. The fact that a law is in the process of being signed when the President declares his intent to ignore it, is irrelevant. If the President has the power to ignore this kind of law, he has the power to ignore laws that were in effect when he took office.

The part the executive branch plays in the constitutional balance of powers is in the need for any Administration to set priorities in the laws that it enforces. Resources are finite and must be rationed. The Clinton Administration put more importance on civil rights laws than the Bush Administration, which puts more emphasis on enforcing child pornography laws. But the constitutional charge of the President is to make sure all laws are faithfully administered; he has no power to ignore or interpret.