Background
In December 1965, John and Mary Beth Tinker and their friend Chris Eckhardt wore black armbands to school in Des Moines, Iowa, to protest the war in Vietnam. School officials told them to remove the armbands, and when they refused, they were suspended (John, 15, from North High; Mary Beth, 13, from Warren Harding Junior High; and Chris, 16, from Roosevelt High). With their parents, they sued the school district, claiming a violation of their First Amendment right of freedom of speech. 

Ruling
The Supreme Court sided with the students. Students and teachers don't "shed their constitutional rights to freedom of speech or expression at the schoolhouse gate," the Court said. 

The Court did not, however, grant students an unlimited right to self-expression. It said First Amendment guarantees must be balanced against a school's need to keep order: As long as an act of expression doesn't disrupt classwork or school activities or invade the rights of others, it's acceptable. Regarding the students in this case, "their deviation consisted only in wearing on their sleeve a band of black cloth," the Court said. "They caused discussion outside of the classrooms, but no interference with work and no disorder." 

Impact
In 1986, applying the "disruption test" from the Tinker case, the Supreme Court upheld the suspension of Matthew Fraser, a 17-year-old senior at Bethel High School in Tacoma, Washington, who gave a school speech containing sexual innuendos (Bethel School District v. Fraser). The Court said "it is a highly appropriate function of public school education to prohibit the use of vulgar and offensive terms in public discourse." 

Lower courts have relied on Tinker in rulings on school attire, allowing nose rings and dyed hair, for example, but disallowing a T-shirt displaying a Confederate flag. 

In June, the Supreme Court weighed in on another student expression case, Frederick v. Morse, ruling that schools can limit student speech that seems to advocate illegal drug use. The case concerned Joseph Frederick, an 18-year-old senior at Juneau-Douglas High School in Alaska, who was suspended in 2002 for holding a banner that said "Bong Hits 4 Jesus" while standing across the street from the school during the Olympic torch relay.