The school district in York, Pennsylvania has come to a compromise of sorts on the use of the book Of Pandas And People (1989) in the classroom. This book is controversial because it includes various ID elements. I haven't read it, but glancing through it, there are some pretty objectionable statements--statements that show how illusory is the attempted distinction between creationism and ID.
For example, the introduction discusses "design inference" and makes an analogy between the "messages" in DNA and a message written in sand on a beach:
Are natural causes capable of producing these kinds of patterns [in DNA]? To say that DNA and protein arose by natural causes, as chemical evolution does, is to say complex, coded messages arose by natural causes. It is akin to saying "John loves Mary" arose from the action of the waves, or from the interaction of the grains of sand. It is like saying the painting of a sunset arose spontaneously from the atoms in the paint and canvas.... If science is based upon experience, then science tells us the message encoded in DNA must have originated from an intelligent cause.
Then there's this subtle argument that schoolchildren should look for supernatural causes of events in the world:
The Darwinist concludes from [the fossil record] that the ones in the lower strata evolved into the ones in the higher strata.
This conclusion must be drawn, however, in the absence of empirical evidence of a chain of fossils leading from lower organisms to higher ones. It is a conclusion shaped as much by philosophical commitments as evidence. If we see one organism followed by another, and we assume that only natural causes were at work, then we really have no choice but to conclude that the earlier organism evolved into the later one.
There is, however, another possibility science leaves open to us, one based on sound inferences from the experience of our senses. It is the possibility that an intelligent cause made fully-formed and functional creatures, which later left their traces in the rocks. We simply work backwards from the fossl to the creature to message text in DNA, to the intelligent cause. We are free to take the evidence where it leads. If there is evidence for natural cause, then we conclude descent. If there is evidence for intelligent cause, then we conclude design. On both sides, the decision one ultimately makes regarding the fossils rests on philosophical commitments as well as on empirical data.
Id. at 26-26 (emphasis original). Even assuming (purely for the sake of argument) that "equal time" were an appropriate educational perspective, this sort of rhetorical trick is hardly "equal." The emphasized phrase is just what differentiates science from non-science, and since it's science, and not religion, that they're supposed to be teaching in science class, it's entirely inappropriate to subtly encourage students to assume that supernatural causes are at work. (We've mentioned Of Pandas And People before (here and here)).
The school officials in York have decided not to require the use of Pandas as part of the curriculum, but have instead decided to offer the use of the book to teachers. What exactly this means isn't clear to me; according to the article the book "will be available to students or teachers who want to use it as a reference in biology class...said Superintendent Richard Nilsen..... Nilsen compared the use of the book to the use of maps in a classroom." This seems to be intended to avoid a vote by the school board, and to allow teachers to decide whether to use the book or not. But in a case where a teacher chooses to use the book, this will hardly absolve the school of any potential First Amendment violation. If this book is used to teach children creationism, then the school is violating the First Amendment, regardless of whether the book is required or not.
In Edwards v. Aguillard, 482 U.S. 578 (1987), the Supreme Court held that the Establishment Clause was violated by Louisiana's attempt to require "equal treatment" of evolution and creationism. The reason was that the law requiring "equal treatment" violated the test established in Lemon v. Kurtzman, 403 U.S. 602, 612-613 (1971). That test says that an act by the government tends to "establish" religion if it: (1) was undertaken for other than a secular purpose, (2) either advances or inhibits religion, or (2), results in an excessive entanglement of government with religion. The Court found that the "equal treatment" law violated part one of this test: "the Act's stated purpose is to protect academic freedom...[but] the Act was not designed to further that goal.... the Act does not serve to protect academic freedom, but has the distinctly different purpose of discrediting evolution by counterbalancing its teaching at every turn with the teaching of creationism...." Edwards, 482 U.S. at 586-89 (citation and quotation marks omitted). Likewise, although the York decision may be made in the name of "equal time," the fact is that "the preeminent purpose...was clearly to advance the religious viewpoint that a supernatural being created humankind." Id. at 591.
Now, the Edwards Court did emphasize that one problem with the Louisiana law was that it curtailed the academic freedom of teachers. But the fact that that concern may not be as strong here does not mean that the York decision avoids the problems of the Establishment Clause. Teaching school children that "[t]o say that DNA and protein arose by natural causes...is like saying the painting of a sunset arose spontaneously from the atoms in the paint" is not only bad science, not only a blatant mischaracterization of evolution, not only an attempt to mislead schoolchildren, but it is undertaken with the conscious purpose of propagating a religious viewpoint in a government school--to instruct them to "conclude design"--and that violates the Establishment Clause. (The schools could constitutionally use Pandas to demonstrate the flaws of creationism; by pointing out, for instance, the inaccuracy of the painting analogy. See id. at 593-94. But teaching the book as it was intended is unconstitutional.)
Evidently, Americans United for Separation of Church And State have threatened a lawsuit. I think they have some pretty strong grounds.