Some of the most important decisions that influence the public's knowledge aren't made by scientific societies and they don't take place in Washington DC. For the most part, they're made in the capitals of each state, as each has its own standards for what students leaving its public schools should know. Those standards set lesson plans and help decide which textbooks are acceptable.

That latter feature means that states with large student populations, like Texas and California, have an outsized influence on education in other states, as textbook publishers work hard to ensure that their products can sell in the largest markets possible. So the state school board in Texas, an elected body that approves education standards once a decade, can have a widespread impact on the US education system.

Unfortunately, the schoolboard in Texas has been a mess. Elections with tiny voter turnouts have put in place religious and ideological warriors who want to rewrite textbooks in the image of their own beliefs, disregarding the expertise of the people who actually know the subject areas at issue. Their contentious assault on science and history standards, which took place in 2010, has been captured in the film The Revisionaries, which PBS' Independent Lens will be showing this coming week.

The process for creating Texas' educational standards is mostly a sound one. A panel of educators and subject experts, often drawn from the academic community, decided which subjects are most relevant and what students should know about them. The standards are then handed over to the board for approval. But the soundness ends there. The board, which may not (and in many cases, does not) have expertise in these subject areas, is allowed to delete, edit, or replace any of the standards recommended by the experts.

And oh boy, do some of them relish the chance. You can see how much respect then-Board Chairman Don McLeroy has for expertise in the clip below, where he wonders why none of them support his tortured misrepresentation of Stephen J. Gould.

McLeroy, a young-Earth creationist who thinks the world is 6,000 years old, is one of the center points of The Revisionaries, which opens with him being grilled in the state capital. He was nominated by Texas governor Rick Perry for another term as Chair at a time when, as one of his questioners notes, there were 11 bills under consideration to strip him of his existing powers. Yet somehow, he came within two votes of being approved.

The movie follows the testimony and actions of the board as it tears through—and in some cases, tears up—the science and history standards that were forwarded to them. It uses footage of hearings and votes, along with interviews of many of the participants, including a professor involved in writing the science standards, and Kathy Miller of the Texas Freedom Network, an organization dedicated to limiting the impact of the board's more ideological members.

And they are seriously ideological. McLeroy is quoted as saying, "education is too important to not be politicized," while fellow board member Cynthia Dunbar claims that "education is inherently religious." And she apparently treats the board meetings the same way, as she's shown giving an opening prayer in which she calls for Jesus to help everyone recognize that the US is "a Christian land, governed by Christian principles."

The existing Texas science standards had language that called for the "strengths and weaknesses" of evolution to be taught. That language has opened the door to the sorts of spurious criticisms that McLeroy is fond of (and apparently, subjects some of his dental patients to). So when the proposed new standards came to the board without any mention of strengths and weaknesses, McLeroy and others fought hard to put them back in. As a compromise, the board simply renamed them to "analyze and evaluate," creating awkward results like instructing students to "analyze all sides of scientific information" about evolution.

If anything, the history standards were worse. Dunbar claims she's a "big fan" of Thomas Jefferson, but thinks a "secular humanistic ideology" has clouded current interpretations of his work. So she cuts him out of the standards on the Enlightenment and its influence on the US' founding documents, instead substituting in pre-enlightenment figures like Thomas Aquinas and John Calvin. Further revisions to history come rapid fire, as others try to add the Heritage Foundation, Moral Majority, and NRA to a section on the '80s, and another person tries to make sure Barack Obama's middle name (Hussein) is added to the text where his name appears.

One board member, looking at the results, is seen saying, "I feel that I have let down the students in our state because all those kids in our schools right now, when they get to college, they're going to learn the real history."

The movie ends with McLeroy losing his reelection bid by a few hundred votes, but already thinking about running again at his next opportunity. But some of his many opponents note that the changes he helped make to the standards will be influencing entire generations of students before they're next revised in 2020.

Enough people describe the whole process as a mess that it's no surprise The Revisionaries struggles to lay it out in a narrative. The challenge is made larger by the filmmakers' decision to provide little framing for the footage, other than sporadic notes scratched on a blackboard to give some sense of the timing and location of the clips. As a result, the movie really doesn't work if you go into it hoping to get a history of the Texas school board. In fact, it would probably be better if you went in to things with a rough outline of the events (the one in this review would be enough).

But if you've got that, the film is a fascinating glimpse into the sorts of thinking that drive the public controversies that have happened in Texas and elsewhere. The issue is probably best captured by some footage of McLeroy away from his work on the school board, teaching a Sunday School class at his church. In tackling Noah's Ark, he only spends a brief moment on the moral import of the story, and then he's off with a scale model of the ark, discussing how its interior could have been organized. Before the scene ends, the children are out on a soccer field, laying out the shape of the ark and counting out known species of animals, all in an effort to show it could work.

For some people, it's not enough to have beliefs. The facts have to be made to comport with them, and everybody else then has to agree with those facts.

The Revisionaries will be appearing on PBS' "Independent Lens" this week. You can find out more details at the PBS site.