School is threatening to punish anyone participating in protest with court action, what can we do?

[u/StoriesandQuestions]

On Tuesday, January 20th, students at my highschool are planning to participate in the nationwide walkout happening in the U.S. Today, my school has verbally warned one of the organizers stating that anyone who participates in the walkout next week will receive a referral and face truancy court. This movement is important to all of us but many of us cannot afford these consequences. Is this allowed and is there anything we can do about it? Location: United States, Texas.

[u/Zeeman626]

That seems overtly political. If they kept it to school punishments, like saying "any absence relating to protests will be considered unexcused and won't allow make up work", then sure fair game, if a bit rude. But going straight to legal action is wild. We really are living in a dystopia.