Legislation proposed across the country since Donald Trump’s election threatens to bring climate change denial into the classroom under the guise of “academic freedom.”

Currently, six states have legislative measures pending or already on the books that would allow anti-science rhetoric, including the rejection of global warming, to seep its way into schools’ curricula. While these types of proposals have become fairly routine in certain states, some of the most recent crop have advanced farther than in the past.

Senate Bill 393 in Oklahoma, for example, would permit teachers to paint established science on both evolution and climate change as “controversial.” The “controversy,” however, doesn’t really exist — more than 97 percent of actively publishing, accredited climate scientists agree that global warming trends over the past century are directly attributable to human activity. And some teachers might already be misleading students.

Since its initial proposal in early February, the bill passed out of the Senate and into the House, where it circumvented the House Education Committee and now heads for a full House vote.

“It’s important to note that this exact bill in Oklahoma has been proposed in the past seven times, and it’s only this year, at a time when there’s federal policy that’s egregiously anti-science, that the bill made it so far,” said Lisa Hoyos, the director of Climate Parents, a Sierra Club–affiliated organization that supports climate change education. In fact, the bill’s sponsor, Republican Sen. Josh Brecheen, has introduced similar legislation every year since 2011. He’s said he wants “every publicly funded Oklahoma school to teach the debate of creation vs. evolution.”

A bill similar to Oklahoma’s is currently working its way through the Texas Legislature. And Florida has two bills pending aimed at letting local residents object to the use of certain instructional materials, such as textbooks that teach human-induced climate change, in public schools.

Some states are passing resolutions, which have a less direct influence but send strong signals about where the state Legislature stands on climate change. In February, Indiana successfully passed its Senate resolution supporting teachers “who choose to teach a diverse curriculum,” giving climate denial and creationism the chance to enter classrooms. A similar “academic freedom” resolution has already made its way through the Alabama House. Finally, Idaho locked in a legally binding Senate resolution in March that deletes material about climate change and human impact on the environment from the state’s science standards.

“Academic freedom bills are the new normal,” said Glenn Branch, deputy director for the National Center for Science Education. According to him, state legislators across the country have filed over 70 academic freedom bills since 2004. That’s when state-level legislation began using vague language to protect teachers’ “academic freedom” by permitting educators to teach about the “strengths and weaknesses” of existing scientific theories. The bill pending in Texas, for example, includes “climate change, biological evolution, the chemical origins of life, and human cloning” among its controversial theories.

“We’re very familiar with this type of language, and it has clearly morphed from the anti-evolution education perspective into the anti-climate change perspective,” said David Evans, executive director of the National Science Teacher Association, which played a key role in shaping the Next Generation Science Standards. The standards, adopted by 18 states and Washington, D.C., since 2015, included the first-ever recommendations for students to learn about human-induced global warming.

These old proposals are being made new again along with a stark ideological switch at the federal level. The president has called climate change a “hoax.” The EPA administrator doesn’t believe carbon dioxide contributes to global warming. And the White House’s continued rollback of environmental regulations reflects those viewpoints. In fact, a series of Pew studies shows 2016 marked the largest gap yet between Republicans and Democrats over belief in human-caused global warming.

“It’s no coincidence when you have an administration banning climate science material from federal websites that science deniers in states would feel emboldened. But at the end of the day, it’s our kids that get shortchanged,” Hoyos said. Her organization, Climate Parents, is circulating a petition — with over 2,250 signatures so far — that urges Republican Gov. Mary Fallin to veto Oklahoma’s bill and stand by the science standards she passed in 2014. While groups like Climate Parents, the National Science Teachers’ Association, and the American Association for Advancement in Science have all openly opposed the passage of Oklahoma’s bill, no group has promised a legal challenge — mostly because no one quite knows what that would look like.

“Laws like these aren’t easy to litigate against, unfortunately,” Branch said. “If [Oklahoma’s bill] were enacted, it would be hard to argue — between its vagueness and its not requiring anybody to do anything — that on its face, it is unconstitutional.” The laws permit, rather than require, teachers to miseducate students on the grounds of scientific “controversy.”

These new “academic freedom” bills cast the word “controversy” precisely in such a way that they’d be able to withstand a court challenge, according to Evans. Now, as conflicts over science education have expanded beyond just evolution and creationism, legislation purposely doesn’t explicitly ban or endorse either side to avoid violating the First Amendment’s establishment clause.

“I’m not uncomfortable with teaching science controversy, but I am uncomfortable with teaching a controversy where there isn’t one in the science. If you want to debate the evidence for and against dark matter versus a modified theory of gravity, that’s a good controversy to bring up in the classroom,” Evans said.

As these bills continue to move forward, the lack of legal weapons worries many educators, especially after free-market think tank The Heartland Institute has vowed to send anti-climate change books and DVDs to every public school in the country.

“There’s a very clear anti-science threat right now that’s in practice,” Evans said. His organization, with around 100 others, endorsed the March for Science in Washington, D.C., and more than 400 satellite events on Earth Day last Saturday. Thousands poured into the streets with a mission to uphold and protect scientific integrity and transparency for the common good.

With voices on both sides of the climate debate growing louder than ever, how far this spate of new bills will travel remains to be seen. But parents and teachers won’t stop fighting.