Texas Gov. Greg Abbott on Monday penned a letter to the Texas Association of School Boards and asked the group to remove books he claims "promote pornographic or obscene material," firing the latest salvo in the political fight to control what's taught in state classrooms.

The letter, addressed to Texas Association of School Boards executive director Dr. Dan Troxell, says the board has an "obligation to determine the extent to which such materials exist or are used in our schools and to remove any such content."

Abbott did not cite specific examples of books that may contain such materials.

The association has not yet issued an official response, but a spokesperson said in a statement to NPR that the group "did not believe it had authority over school districts" to remove books from libraries and "does not set the standards for instructional materials, including library books."

CNN reports that Abbott's letter came a week after state lawmaker Jeff Cason called on Texas' attorney general to investigate books he considered to be "pornography."

Also, last week, state Rep. Matt Krause announced he was leading an investigation into a list of 850 books that may be in school libraries despite "objections from students, parents and taxpayers." A Dallas Morning News investigation has found that a significant portion of the books on the list were written by women, people of color or LGBTQ authors.

Texas is just one of several states where conservative lawmakers are taking the "culture wars" into the classroom. Republican Glenn Youngkin prevailed in the Virginia gubernatorial election earlier this week after raising concerns about the use of "critical race theory" in classrooms.

MANHATTAN BEACH, Calif. (AP) — California Gov. Gavin Newsom has signed legislation that allows ownership of a prime beachfront property to be transferred to heirs of a couple who built a resort for Black people in the early 1900s.

The property was purchased in 1912 by Willa and Charles Bruce, who built the first West Coast resort for Black people when segregation barred them from many beaches.

The family was stripped of the land by local officials in the 1920s.

"As governor of California, let me do what Manhattan Beach apparently was unwilling to do, and I want to apologize to the Bruce family for the injustice that was done to them a century ago," Gov. Newsom said.

The legislation signed Thursday was necessary to allow the start of the complex legal process of transferring ownership of what was once known as Bruce’s Beach in the city of Manhattan Beach and has been owned by Los Angeles County.

"We stand here ready to transfer this property back to the rightful owners," said California Sen. Steven Bradford.

"We will not tolerate the schools to indoctrinate our children," a woman said during a school board meeting in Fort Worth, Texas recently. 

Scenes like this during a Fort Worth, Texas, school board meeting are playing out across the country: all focused on the debate over critical race theory -- something that has become a powerful rallying cry among conservatives. 

"But they have to get it out of our schools and they have to get it out of our workplaces," said former President Donald Trump. 

Critical race theory -- or CRT -- is a decades-old academic framework that explores the intersection of laws and race within society. For example, a CRT-focused course might study how housing laws have kept people of color out of certain neighborhoods, or how drug laws have disproportionately impacted Black people. It's usually taught in various disciplines in college or during graduate-level studies. Largely not in K-12 classrooms, according to experts. 

"Please refrain from disrupting the board meeting," replied a member of the Fort Worth Independent School District.

The Fort Worth Independent School District, like other school systems in the state, says it is not part of its curriculum.  But some families here allege the theory is being used in the classroom.

"I think what they need to focus on is teach[ing] reading and teach writing and teach math and teach government and history," said Sharron Hives. "The things that have been taught, you know, down through the years. I don't think that critical race theory and that ideology needs to be taught in school." 

Opponents of CRT here in Texas who declined to go on camera called the theory divisive and the polar opposite of what American values represent. Some also say they gathered information about the theory via conservative media outlets, and they believe school districts that say they aren't teaching critical race theory are simply doing it under a different name. 

"A lot of them are getting their information off of biased news sources and they are being told that it's being taught in the schools," said high school world history teacher Diane Birdwell.

"Number one, it's not being taught [in] school, especially in high school. Number two, the image of teachers trying to make kids feel bad about their race goes exactly against what we are as teachers."

Texas and several other states have moved to put laws into place targeting the way teachers can talk about racism in the classroom. One expert says a common theme has emerged amid the ongoing debate.

"It really is a more advanced understanding of our American experiment," said Vida Robertson, who is the Director of the Center for Critical Race Studies. "Again, however, that doesn't keep the right from organizing a boogeyman so that folks who have both kindergartners and future college students might be able to unite around this monster."

The Texas law does not mention "critical race theory" but it does put up limitations on how teachers discuss race, sex or current events in the classroom. And Texas Governor Greg Abbott is further targeting CRT during a July special legislative session. 

Birdwell, who's also a member of the National Education Association, says she is hearing concern from teachers worried what impact the law could have on their ability to educate students. 

"We are getting a lot of concerns from our members and we're addressing them and we've told them to just teach, do your job, do it well and teach the facts, and the facts… well, the children will figure out what's with the facts. And if parents have concerns, show them your materials."

This story originally reported by Willie James Inman on Newsy.com.

The idea of teaching critical race theory has become a contentious issue. Florida, Oklahoma, Texas, and a handful of other states have banned the teaching of critical race theory in K-12 classrooms in recent weeks.

But, what is it?

“Critical race theory is the theory that our systems in this country are bound up in race,” Kerry Goldmann, a lecturer at the University of North Texas, said.

“It pretty much offers a space where we recognize how race plays a part in everything that happens in the lives of people in this country,” Jalaya Liles Dunn, the Director of Teaching Tolerance program at the Southern Poverty Law Center, said.

The center is a national nonprofit that specializes in civil rights and public interest cases.

“The idea was to research the institutionalization and the systematic use of racism or some kind of discriminatory behaviors in laws, policies, behaviors, social norms,” Diane Birdwell, a high school history teacher, said.

Birdwell has been a teacher for over two decades in Texas -- one of the states that recently banned the teaching. She said while she’s not opposed to critical race theory, it’s not commonly seen in her history lessons.

“It’s not taught in schools. It’s not a curriculum. It’s a theory,” she said.

Birdwell said what she teaches focuses a lot on primary documents, having students look at context, perspective, and purpose.

“What we’re trying to teach students is the why,” she said. “Critical race theory doesn’t mean you ignore anyone. It doesn’t make anyone evil or bad. It just says make sure you tell the story.”

However, that’s not how everyone sees it. Parents and teachers have been voicing their opinions across the nation.

“How are our youngest learners supposed to love and accept one another when they are told they are inherently bad or inherently a victim because of the color of their skin,” one woman said at a board meeting in Wisconsin.

“I don’t think children should be focusing on the color of their skin, focusing on past traumas,” another woman in Florida said, referring to critical race theory.

“I think the reaction to critical race theory is fear, to be honest. I think it’s fear of accepting that our history is not always pleasant, it's not always pretty, and it was downright wrong in a lot of cases,” Birdwell said.

While it’s creating quite a bit of buzz, University of North Texas history professor Kerry Goldman said up to now, critical race theory was mostly used by academics.

“It really hasn't been brought to the forefront of the public realm until really this past year, and it’s been really politicized,” she said. “Critical race theory started as an intellectual movement and a legal theory in the mid-1970s and really formally organized by the 1980s.”

Goldmann said it started as a law theory and slowly found itself in other fields such as humanities and social sciences. As for banning it from classrooms, Goldmann said she’s seen instances like this happen before.

“If you look at the early to mid 20th century, you had a lot of pressure put on educators K-12 to not teach about class inequality. And the reason for that is because politicians were fearful that children would be indoctrinated into ideals of communism simply from learning about class inequality existing,” she said.

“Teachers have a fine line to make sure students feel safe, but understand they don't live in a safe space. The world is not safe for them, not for all of them,” Jalaya Liles Dunn said.

For teachers like Birdwell, she plans on continuing to teach history with the facts she has at hand, with context. “Part of history is to see the things that make us uncomfortable, that make us unhappy,” she said.