Get in the way of the profits of any business that deals in animal research or uses or sells animal products (and you might just be a terrorist)

You may not have heard of the Animal Enterprise Terrorism Act, because the very first prosecution under the 2006 law is currently underway in San Jose, California. In the case, USA v. Buddenberg, four animal rights activists are accused of chanting, making leaflets and writing with chalk on the sidewalk in front of a senior bio-researcher's house, as well as using the internet to research the company whose actions they planned to protest. Under the AETA, they are charged with acts of animal enterprise terrorism.

The AETA classifies a person who "intentionally damages or causes the loss of any real or personal property" or "intentionally places a person in reasonable fear of" death or serious bodily injury as terrorists when they act for the "purpose of damaging or interfering with an animal enterprise." It imposes penalties accordingly. At first blush, this may not sound so bad. But a closer look exposes serious problems: the AETA can be read to reach so many different types of protests and people, and it is written in language so vague, it is impossible for someone to know whether their actions might be covered under the AETA, and thus great swaths of protected speech are in danger of being silenced by the law.

To understand the fundamental threat to free speech, the First Amendment and the right to protest that the AETA poses, it might help to unpack the words "Animal Enterprise," "Terrorism," and "Act."

Under the law, an animal enterprise includes any business that deals in animal research or uses or sells animal products. This could be read as anything from a lab conducting medical research on monkeys to a gas station that sells beef jerky.