On Dec. 10, 2007, the U.S. Court of Appeals for the Ninth Circuit ruled several provisions of the Patriot Act unconstitutional. The portions of the 2001 law in question criminalized any support for nonviolent activities of groups deemed by the Bush administration to be "terrorist organizations."

In the ruling — Humanitarian Law Project v. Mukasey — Judge Harry Pregerson held the language of the law is too vague because a person of ordinary intelligence would not be able to distinguish which types of activities or behaviors are illegal. In his opinion, Pregerson wrote, "Vague statutes are invalidated for three reasons: 1) to avoid punishing people for behavior that they could not have known was illegal; 2) to avoid arbitrary and discriminatory enforcement by government officers, and 3) to avoid any chilling effect on the exercise of First Amendment freedoms."

The provisions of the Patriot Act of concern in this case are amendments to the Antiterrorism and Effective Death Penalty Act (AEDPA), which enabled the U.S. Secretary of State to identify any group as a "foreign terrorist organization." Additionally, the law made it a crime — punishable by up to ten years in prison — for anyone to support even the nonviolent activities of such designated groups. The recent judgment upholds a 2005 ruling in which a U.S. District Court judge in Los Angeles, CA, found the parts of the law defining provision of training, expert advice or assistance, personnel, and service to be unconstitutional because there is "no apparent limit" to presidential authority to label groups as terrorist organizations. The 2005 judgment stopped the federal government from putting these provisions into effect against the groups named in the plaintiffs' complaint.

In their original complaint, the Humanitarian Law Project (HLP) asserted that the law compels an unfair guilt by association standard under which innocent individuals could be punished for supporting the good works of an organization that also engages in illicit activities. HLP contended it had been forced to stop its human rights and conflict resolution training for the Kurdistan Workers Party in Turkey and the Liberation Tigers of Tamil Eelam in Sri Lanka out of fear of legal sanctions because the groups have been designated as terrorist organizations. Both engage in wide range of nonviolent, humanitarian activities as well as violent ones. The plaintiffs argued that, as such, the enforcement of the law violated their First and Fifth Amendment rights.