A Boston federal judge threw out a lawsuit filed by animal rights activists who challenged the constitutionality of a federal law criminalizing violence and property damage against animal-related organizations and the people who work for them.

U.S. District Judge Joseph Tauro dismissed the case on March 18 for lack of standing, writing that the plaintiffs’ fear of being targeted for legitimate protest activities were overblown.

"Where Plaintiffs seek to engage in lawful and peaceful investigation, protest, public-speaking, and letter-writing, the court cannot reasonably conclude that these actions fall within the purview of a statute requiring intentional damage or loss to property or creation in an individual of a reasonable fear of death," he wrote.

The five individual plaintiffs, including named plaintiff Sarahjane Blum, sued U.S. Attorney General Eric Holder over the Animal Enterprise Terrorism Act in December 2011. They claimed the law is unconstitutional on its face and as applied.

In his written opinion, Tauro explained that the law criminalizes three things: intentional damage to real or personal property that leads to a loss; intentionally causing someone to fear death or serious injury; and conspiring to or attempting either of the above. "And this is how both the AETA and its predecessor [law] have been enforced," he wrote.

The plaintiffs claimed that they feared that they risked prosecution under the law for expressing their First Amendment rights, but hadn’t proven an "objectively reasonable chill," Tauro concluded.

In practice, the plaintiffs have refrained from constitutionally protected speech because they’re afraid of prosecution as terrorists, according to a formal statement issued by Rachel Meeropol, a senior staff attorney at the Center for Constitutional Rights in New York.

"While the judge’s narrow reading of the statute would solve some of its many constitutional flaws, our clients and other activists have no guarantee that prosecutors, or even other judges, will agree. They will continue to be chilled from speaking out on important issues of public concern until this law is struck down," Meeropol said.

Attorneys from the Law Offices of Howard Friedman in Boston and the Benjamin N. Cardozo School of Law in New York also represented the plaintiffs.

The center said that the activists plan to appeal Tauro’s ruling.

The Justice Department did not respond to a request for comment.

Animal rights activists do have reason to fear the law, said David Nathanson of Boston’s Wood & Nathanson, who filed a pro bono amicus brief for the American Civil Liberties Union of Massachusetts.

Nathanson said the law is "written so broadly that it could be used to brand minor crimes, such as trespassing or graffiti, as terrorism against businesses that use animal products."

Sheri Qualters can be contacted at squalters@alm.com.