No one likes to eat crow. Especially a principal.
On May 28th, Addison Barnes wore a t-shirt to school, in anticipation of a class debate in his "People and Politics" class on immigration. The t-shirt said "Donald J. Trump Border Wall Construction Co." on the front, and "The Wall Just Got 10 Feet Taller" on the back. The assistant principal removed Barnes from the room and told him to cover the t-shirt because it offended at least one teacher and one student. The school's student body is one third Hispanic, and had recently conducted a walkout over immigration. Barnes was told he could either cover the t-shirt or go home. He went home, and the school counted the absence as a suspension.
Freedom of Speech, Just Watch What You Say?
Barnes claimed his First Amendment Right to Free Speech as a student had been violated, and sued. He won a Temporary Restraining Order; the graduating senior could wear the t-shirt for the remainder of the school year -- five days. The judge felt he couldn't rule on the merits of the case yet: balancing the right to core political speech with the effect of the speech on the listener, against the school's belief that the speech would incite violence or "substantial disruption" from student reaction.
Before the case could be ruled on its merits, the two sides settled out of court. The settlement required the school district to pay for $25,000 for Barnes' attorney fees, remove the suspension from his school record, and require a letter of apology from the principal to Barnes. The plaintiffs are declaring a victory for free speech, whether popular or not, but the district claimed it just wanted to strike a compromise and move on.
"Substantial Disruption" Is Incident Specific
In other cases, political messages on t-shirts at school have been declared a "substantial disruption." In a California high school with a large population of Mexican students, two caucasian students were asked to remove their American flag t-shirts on Cinco de Mayo. That request was declared constitutional. At the time, there was a great deal of gang tension and racial violence on campus. The t-shirts were believed to be capable of causing "substantial disruption" among the student body. SCOTUS was asked to review the case, but denied it, presumably agreeing with the 9th Circuit's interpretation of Constitutional Law.
No matter what side of the debate you're on, if you feel your free speech rights have been violated, contact a civil rights attorney to assess the strength of your case.