Free speech film features landmark Tinker v. Des Moines case

Why it matters: The case resulted in a U.S. Supreme Court ruling that confirmed students' rights to free speech or expression in public schools.

Plus: The film features interviews with Mary Beth Tinker.

• She was 13 when she, her brother John and three other students were suspended from Des Moines Public Schools for wearing black armbands in protest of the Vietnam War.

Catch up fast: School officials said the armbands were a distraction to education. The ACLU challenged the case as a violation of the First Amendment.

• Lower court decisions siding with the school were overturned in a 1969 SCOTUS ruling that says constitutional rights do not end at schoolhouse gates.

Yes, but: The court also established guidelines — commonly known as the "Tinker Test" — that say students can't substantially disrupt school or impinge on the rights of others.

The intrigue: The film highlights the reaction to a silent, symbolic protest from a few teenagers and how it developed into a landmark case.

• Her family got hate mail and a bomb threat to their home soon after the school suspensions, Mary Beth says in the film.

Watch it: "First Amendment: Student Freedom of Speech"