Gilkey testified for the plaintiffs in McLean v. Arkansas, the case that challenged the constitutionality of Arkansas's "Balanced treatment for creation-science and evolution-science act" of 1981. In his account of his experiences, Creationism on Trial: Evolution and God at Little Rock (1985), he explained his antipathy to the law: "I came to the conclusion that this law and ones similar to it are ... in fact dangerous to the health of our society; and that through its wide enactment it would represent a disaster to our common life, especially our religious life. ... This law, I was convinced — and this was my subsequent argument — would serve to establish a particular form of the Christian religion in the teaching program of the public schools; therefore, it presented a grave threat to the free religious life of our country."