AMNA NAWAZ: In 2021, an affluent suburban school district in Texas gained national attention when parents and local conservative activists accused the district of indoctrinating students with Critical Race Theory.

That drew the interest of Republican figures across the country and sparked a Christian movement beyond the district's borders to restrict what children are being taught in schools.

Laura Barron-Lopez has that story for our Bookshelf.

LAURA BARRON-LOPEZ: Mike Hixenbaugh has been at the forefront of covering the events in Southlake Texas.

What started as an earnest effort by the Carroll Independent School District to confront racist rhetoric and bullying devolved into a battle about much more.

Conservative parents and activists turned a district cultural competence plan into a fight over protecting their - - quote -- "traditional way of life."

The result?

Books and classroom discussion about race, slavery, and sexual orientation were effectively banned.

In his book "They Came for the Schools," released in May, Hixenbaugh details how this school district became a blueprint for Republicans across the country and exposed their ambitions, which go well beyond controlling what version of American history makes it into high school textbooks.

I'm joined now by the author and senior investigative reporter for NBC News, Mike Hixenbaugh.

Mike, thank you so much for joining us.

MIKE HIXENBAUGH, Author, "They Came for the Schools: One Town's Fight Over Race and Identity, and the New War for America's Classrooms": Thank you.

LAURA BARRON-LOPEZ: When you started investigating, you discovered that there were a number of racist incidents at the schools in Southlake, some that go back decades, but, in particular, in 2018, when a video of white students saying the N-word went viral.

And the district promised action.

What exactly was their plan in response to that?

MIKE HIXENBAUGH: After the video came out, dozens of parents came forward and said, it's not just a video.

My Black child has experienced these kind of racist slurs and jokes in the school for decades.

And so the district put together a committee.

And they formed -- they put together a plan called the Cultural Competence Action Plan.

They worked for two years on this from 2018 to 2020, and the plan essentially called for diversity training for students and teachers, initiatives to try to hire more a diverse teaching staff, a plan to go through the curriculum to make sure that kids were learning an honest and full picture of America's history.

But the plan was released in 2020 in the midst of backlash against the Black Lives Matter movement.

And so when it was released into the community, some conservatives who I guess hadn't been paying attention to the two years of work on the plan, they saw it as this plan that was being shepherded in by the radical left to try to ruin this affluent, successful school district.

LAURA BARRON-LOPEZ: In response, a local conservative group, the Southlake Families PAC, said that they rallied what they called an army to their cause.

How did they convince the community essentially to turn on school district leaders, school board leaders, teachers that many of these people had known for years?

MIKE HIXENBAUGH: It was remarkable to watch, because the people who were advancing this Cultural Competence Action Plan, many of them were themselves conservatives, Republicans.

But the Southlake Families PAC painted anyone who was pushing this plan as a radical leftist, as a Marxist.

And it was around the same time that Critical Race Theory was entering the national conversation, this phrase that Chris Rufo used to try to describe any attempt to address discrimination in schools and other places.

It became a battle between adults over who was welcome in Southlake, whose ideas were welcome there.

And that fight ended up spreading all over the country.

LAURA BARRON-LOPEZ: Chris Rufo, the national conservative activist, what role did he play in taking Southlake and spreading it elsewhere and making it a national cause?

MIKE HIXENBAUGH: After Southlake Families PAC got organized, they put together a slate of conservative school board candidates whose mission was to destroy and defeat that diversity plan.

The Southlake Families PAC candidates won in a landslide election in may of 2021.

And Chris Rufo, after that, was one of many conservative voices who then held up the election in Southlake as a model to be copied in schools all over the country.

LAURA BARRON-LOPEZ: You say that the end goals were bigger than even just teachings about history, stretching all the way to making schools more explicitly Christian.

What is the end goal here, and where are we seeing it in other places?

MIKE HIXENBAUGH: There are elements of the Christian right in America that have long argued that the separation of church and state is a myth, that our country began to decline in the 1960s, when prayer and mandatory Bible readings were removed from schools.

And they have seized on this moment to say, parents are upset about schools.

This is our chance to try to chip away at those foundational principles.

And so you're seeing in Texas and all over the country moves to, in this moment, not just remove LGBTQ content from schools or to ban how -- restrict how teachers talk about race and racism, but to replace those things with Christian symbols.

There's bills to mandate the Ten Commandments be hung in every classroom, to put Christian chaplains in schools to replace counselors and therapists, and to bring the Bible back into school and have kids read from that as part of their social studies curriculum.

They are counting on lawsuits.

Some activists have said explicitly that -- told school districts or school board members, hey, if you bring prayer back to school, hopefully, someone will sue you.

We can take that to the Supreme Court and we can win this for America.

LAURA BARRON-LOPEZ: More than three years into this, what does the resistance movement look like outside of Southlake and the other communities that are facing book bans and having difficulty when it comes to being able to teach history?

MIKE HIXENBAUGH: What we have seen now all over the country in kind of purple or left-leaning suburbs coalitions of progressive and moderate conservative parents banding together, forming their own political action committees, running their own slate of candidates.

And so we're seeing that in different places across the country, where Moms for Liberty isn't winning in a lot of places.

Their ideas are not necessarily broadly popular, even among a lot of conservatives.

And so we have seen kind of a wave of victories for the other side.

LAURA BARRON-LOPEZ: Based on all of your reporting in Southlake and the larger movement to revise American history, what do you think is at stake this election cycle?

MIKE HIXENBAUGH: I think about stories like a teacher I highlight in the book named Christina McGuirk, a fourth grade teacher who got into education because she wanted to live out her own Christian faith by showing kindness to kids and teaching them a real accounting of America and how to be kind to each other.

But as a result of her speaking out about these issues, she was forced out of her job.

And we're seeing that repeated all over the country.

Teachers are weighing whether or not they're going to stay in the classroom.

And, at the same time, families, parents are looking at what's happening and wondering, do I want to keep sending my kid to this school?

Do I want to still live in this community?

And, as a result, people's lives are literally being upended.

LAURA BARRON-LOPEZ: Mike Hixenbaugh of NBC News, thank you.

MIKE HIXENBAUGH: Thank you.