The problem with ID is that it posits something (super-natural intelligence that guides evolution) that is not scientifically testable. That very fact alone means that it is not a valid scientific theory. Therefore, it is not valid to teach ID in the science classrooms of public schools.
Simple logic is all that is required to reach this conclusion, but unfortunately "activist judges" are required to stop those who would turn science into public-opinion polls.
Does the Theory of Evolution have problems? Of course it does. So do our theories dealing with particle physics, for example, but you don't hear activists trying to push non-scientific alternatives. But the so-called "Science Establishment" can and does modify those theories as better explanations come about. ID is not one of those better explanations.
Reading the court transcripts is an excercise of perseverance, but I was struck by how comically Michael Behe (a leading proponent for ID) evaded stating the mechanism behind ID after having been caught to have said, "Intelligent design theory focuses exclusively on the proposed mechanism of how complex biological structures arose."
(www2.ncseweb.org/kvd/trans/2005_1018_day11_pm.pdf page 63ff)
Could you mention in the science classroom that it is wrong to steal? "It is not a valid scientific theory"!