Having spent an evening talking with a proponent of intelligent design, I am impressed by the careful wording that is used.
The fundamental concept of ID implies the existance of an Intelligent Designer. However, ID is careful to avoid attempting to identify who or what that designer might be.
They state they do not care who the designer is, just that there is one. Any possible reference to the supernatural is avoided at all costs.
So, ID is science is it? Apparently, they claim, yes.
So, being science it is limited to the realm of reality? In order to be science it must be.
So the intelligent designer exists within the realm of reality and is therefore not supernatural!
At this point, certain questions spring to mind
Who made the intelligent designer? Who's his mother? Where did she come from?
Even if you invoke an infinite lineage of intelligent designers, you still end up outside of the realm of reality.
You can't escape it - ID eventually needs a supernatural being, which means it's faith and not science.
Now there is nothing wrong with ID being a matter of faith; and that's exactly what it is.