This is protected under the freedom of expression. Students are permitted to wear what they like unless their attire is vulgar or lewd (Bethel School Dist. No. 403 v. Fraser, 478 U.S. 675 (1986)), promote illegal drug use (Morse v. Frederick, 551 U.S. 393 (2007)), or are likely to cause serious disruption at school or violate other students’ rights (Tinker v. Des Moines Independent Community School Dist., 393 U.S. 503 (1969)). Teachers should be granted the same freedoms.