Mandating acceptance of a religious tract as an acceptable science textbook is establishment of religion.
Have you even read the constitution?
When I was in high school one of the mandated books in my Literature class was Siddartha by Herman Hesse (which is a book that extolls the virtues of Buddhism). Nobody complained. Quite frankly if mandating a suggestion to read a certain book is an establishment of religion, then mandating the teaching of evolution could also be considered an establishment of religion as it contradicts the deeply held religious beliefs of some people.
But the fact is that neither of them is "an establishment of religion." Both may be considered as a tacit endorsement of a religious position, but no reasonable person could conclude that what the Dover School board did was in any way "an establishment of religion."
Read the history of the First Amendment and you will see what the founders intended by that clause. The fact is that the same Congress that passed the first amendment also passed a resolution and law mandating the teaching of the Bible using public funds in the Territories of the United States. That was not an establishment of religion then and this is not one now.
I am amazed at all the people on this board -- supposed conservatives -- who have bought into this idea of the constitution being a living document. It is not. It is a contract.
I'm sure that if a judge had found that the teaching of evolution violated some obscure clause in the Constitution, that you guys would be all over that decision like white on rice. Just because you won on this issue does not mean you actually won anything. This is a pyrric victory for any conservative who believes in evolution.
Hopefully because this decision is so overreaching, it will sound the death knell for the Lemon Test. In that sense it may yet be a victory for the principles of original intent.