ID is not science. It is religion in disguise, dreamed up after the U.S. Supreme Court removed creation "science" from the classrooms. And creation "science" was the response to an earlier court decision removing creationism from the classrooms.
Further, ID cannot live within the normal rules of science. The desire to be considered a scientific "theory" without going through the normal process (data, hypothesis, testing, peer review, etc.) is just the first problem. Second, ID has no research program. It is being entirely pushed in the political arena by the Discovery Institute, by lawyers, PR flaks, journalists and the like. That does not impress scientists much. Finally, ID does not follow the scientific method. It starts with the answer it wants and seeks to "prove" that answer by any means possible--except science and the scientific method.
Here is a good article on the subject: What Is The Scientific Theory of Intelligent Design?, by Lenny Flank. This goes into much more detail.
So what? My point was not to argue that ID is “science” (however you want to define it) but to argue that it is worth teaching IN CONJUNCTION WITH “science” as you define it.