Kindly explain how Intelligent Design Theory in the classroom would interfere with a study of the ToE.
How does ID interfere with the teaching of the ToE?
For one thing, it's a religiously-motivated hypothesis demanding equal weight with a theory that has proven its value in the real world. It teaches students the myth that wishful thinking and "what-if" scenarios are equal to cold, hard facts, and that they can choose one or the other with no hard consequences.
It muddies the waters. It's analogous to saying "2+2=4, but in an alternate universe 2+2 might equal 5, or 6, or watermelons."
ID also cannot be considered a scientific theory until it starts to make accurate predictions based on known facts. If it can't do that, why teach it at all?
A teacher's attitude towards the subject can strongly influence which viewpoint the student ultimately accepts. Unless there is constant monitoring in the classroom, or a non-believing student complains, there's nothing to stop a teacher from waxing poetic that there must
be a designer (because pussycats and flowers and lah-dee-dah), and "Oh, I have to teach you this evolution crap too but we'll just do that till recess."
Finally, this whole debate is apples-and-oranges. Intelligent Design is all about origins, whereas evolution is about how existing organisms change over time. ID is in the wrong science course from the start -- It should really be in a graduate-level Biochemistry unit on abiogenesis, where it would get the respect it truly deserves.