The Bill of Rights applies and is of fundamental importance to conservatives. The 1st Amend. provides a Constitutional reason for keeping religion and it's nonscientific creationist and ID claims out of the science class. No religion is to be established by the state. IOWs no one is to corrupt science with nonscientific religious claims and nonscientific claims based on religious motivations.
Both creationism and ID are nonscientific. Both claim the laws of physics are insufficient to govern the world. That is not what is found scientifically. If you want to teach that to your kids, enroll them in a parochial school, or homeschool them. The first Amend. forbids forcing religion though the public school system, especially by attempting to forcefully inject the fraud into the science class where it has no place at all.
Parochial (ie Catholic) schools teach normal biology. Some Protestant schools teach creationism as though it were science.