We're just a few days from the 10th anniversary of Kitzmiller v Dover, the case that declared teaching intelligent design in science classrooms an unconstitutional imposition of religion. The sound legal defeat at Dover, however, hasn't convinced people who dislike evolution from trying to limit its use in public education. Instead, they've simply adapted to the new legal environment by developing new tactics.

If all that adapting to the environment sounds a bit like evolution to you, you're not alone. Nick Matzke played a key role in the Dover trial, and he went on to graduate studies in evolutionary biology. In a short report that's being released by Science, Matzke describes how you can apply evolutionary analysis to the dozens of bills that have targeted science education in various states. The results look a lot like evolutionary lineages, with lots of dead ends and the rapid expansion of successful innovations.

Matzke used to work for the National Center for Science Education (NCSE), which helped support the plaintiffs at the Dover trial. He's most famous for finding another evolution analog in a key text: a search of early drafts of the intelligent design book promoted by the school board turned up a "transitional fossil."

Drafts of the book were focused on the overtly religious concept of creationism and used the term repeatedly. But after teaching creationism was declared unconstitutional by the Supreme Court, the drafts abruptly shifted to using the term "intelligent design." Matzke found one draft where the replacement of "creationists" by "design proponents" resulted in the use of "cdesign proponentsists."

Evolution by opponents of evolution

When it comes to science education, there's a long history of similar evolutionary changes driven by the legal environment. Laws ordering the teaching of "creation science" started in response to a Supreme Court ruling that states couldn't simply ban the teaching of evolution. Intelligent design arose in response to the ban on teaching creationism in science classrooms.

Matzke's new paper is inspired by the response to Kitzmiller v Dover, which put an end to the idea of teaching intelligent design (or at least should have; more on that below). Since then, the NCSE has tracked over 70 bills in 16 states that all attempt to protect teachers who present non-standard information in science classes. They typically prohibit any local authority—the school administration or board officials—from disciplining a teacher for using material that presents "the full range of scientific views" on topics that include evolution but sometimes add things like human cloning and climate change.

The bills are intended to provide legal cover for the introduction of creationist material that is presented in a way that sounds scientific to casual observers. In many cases, the legislators who sponsored the bills publicly said as much or had previously introduced bills that were overtly creationists. And in the two states where similar bills have passed, there's evidence that teachers view them that way.

Matzke was curious about how the ideas in the bills spread and where they originated. So he obtained the text of all of them and ran them through an algorithm that reconstructs trees of common descent. The resulting tree is pretty informative.

To begin with, the bills, in the guise of "Academic Freedom Acts," actually predate the Dover case. A series of them were introduced in the Alabama legislature in 2004 and 2005; similar efforts continued through 2009. This approach spread pretty widely, with related text in states like Oklahoma, Maryland, and New Mexico. The pro-intelligent design Discovery Institute also publicized a model bill based on this language in 2007, though it's possible that Discovery had circulated the bill privately before then.

The early origins of this language suggests that the legal defeat at Dover didn't create it but rather selected for it when the dominant approach, intelligent design, was eliminated. But one notable branch in this lineage appeared in Texas in 2011, where the bill's language explicitly promoted the teaching of intelligent design—over five years after it had been declared unconstitutional. This happened again in South Dakota just last year.

Matzke's tree identified a key event in 2006: a Louisiana Parish adopted a policy that covered evolution, the origin of life, human cloning, and climate change. Its language was merged with that of the earlier Academic Freedom Acts, creating a binge of "Science Education Acts" that appeared in Louisiana and a number of other states in 2008. One of these went on to become the first law of its kind to be enacted.

This success inspired copies in states like Texas, Maryland, Missouri, and Virginia. All told, similar language appeared in over 10 state legislatures, although some of these bills dropped specific areas of science. This led to a second success in Tennessee. Critically, this lineage has entirely displaced the earlier Academic Freedom Acts, which have only seen a single version introduced since 2011. In contrast, five science education acts were introduced this year.

Further Reading Tennessee governor allows bill targeting science education to become law

Overall, Matzke concludes that opponents of evolution have reinvented themselves twice over the last dozen years or so, starting with academic freedom bills and later switching to science education acts. During that time, there were also some successful innovations, such as bringing along climate change in an attempt to attract wider conservative support.

But critically, he finds that none of the bills were successful prior to the merging in of language from the Ouachita Parish education policy. That Parish, he notes, has a population of about 150,000. But its policy now influences the education of over 11 million students in two states, with more bills introduced each year.

Science, 2015. DOI: 10.1126/science.aad4057 (About DOIs).