In the latest phase of the nation's mounting political war over transgender people and bathrooms, 11 states are suing the Obama administration over its guidelines for school bathrooms and trans people.

Specifically, the lawsuit is a challenge to a federal guidance telling public schools to let trans students, who identify with a gender different from the one assigned to them at birth, use the bathroom or locker room for their gender identity. The guidance is an implicit threat to states and schools, which could lose billions in federal funding for education if they don't comply.

The lawsuit was filed earlier in the day at a federal court in Texas, Mark Berman reported for the Washington Post. Texas Attorney General Ken Paxton announced the lawsuit at a press conference on Wednesday. Texas is joined by Arizona, Alabama, Georgia, Louisiana, Maine, Oklahoma, Tennessee, Utah, West Virginia, and Wisconsin in the lawsuit.

Paxton is not the first Texas official to take a big public stance against the guidance. In the days after the Obama administration's guidance was announced, the state's lieutenant governor went on Fox News to criticize the guidelines. And Texas Gov. Greg Abbott tweeted, "JFK wanted to send a man to the moon. Obama wants to send a man to the women's restroom. We must get our country back on track."

But the lawsuit is the biggest challenge against the Obama administration's guidance so far, contending that the administration has misinterpreted federal civil rights laws to create new protections for trans people. Obama administration officials "have conspired to turn workplaces and educational settings across the country into laboratories for a massive social experiment," the lawsuit claims, "flouting the democratic process, and running roughshod over commonsense policies protecting children and basic privacy rights." (Read the full lawsuit here.)

The Obama administration's guidance is not legally binding. Although the administration has long interpreted federal civil rights laws that ban sex discrimination, such as Title IX, to protect trans people, not all courts have upheld this interpretation. Still, the administration has suggested that it will file lawsuits against states and schools that allow anti-trans discrimination, as it did against North Carolina. So the lawsuit is likely a preemptive defensive measure for the 11 states involved, none of which apparently want legal protections for trans people in schools.

For more on the debate over trans people and bathrooms, read Vox's explainer.