The American Civil Liberties Union directly participated in this case on the side of Joseph Frederick. The Center for Individual Rights, National Coalition Against Censorship, and other groups that advocate First Amendment protection filed amici curiae in support of Frederick.
The ACLU directly represented Joseph Frederick in this legal matter.  Other groups advocating for the protection of free speech, including the Center for Individual Rights and the National Coalition Against Censorship, also provided support for Frederick by filing amicus curiae briefs.