The U.S. Department of Justice (DOJ) plans to appeal a ruling that a letter sent by anti-choice activist Angel Dillard to a Wichita abortion provider, stating that if she continued providing abortions in Wichita someone might place explosives under her car, is protected free speech, the Associated Press reports.

The ruling came this August in the ongoing federal lawsuit against Dillard, a notorious anti-choice radical with ties to Scott Roeder, the confessed murderer of Dr. George Tiller. In 2011, after Dr. Tiller’s murder, Dillard sent a letter to Dr. Mila Means. At the time Dillard sent the letter, Means was preparing to start offering abortion services at the clinic of the late Dr. Tiller. In the letter to Means, Dillard presented a “vision” of what Means’ life would look like should she start providing abortions in Wichita. In that letter, Dillard explained how thousands of people from across the country were already scrutinizing Means’ background. Soon, Dillard promised, they would know “your habits and routines. They know where you shop, who your friends are, what you drive, where you live,” Dillard wrote. “You will be checking under your car every day—because today is the today someone places an explosive under it.”

Based on the content of that letter, the DOJ sued Dillard under the Freedom of Access to Clinic Entrances Act (FACE Act), the federal law that makes it a crime to threaten or otherwise interfere with access to abortion clinics or providers. According to the DOJ, those statements concerning explosives were sufficient to constitute a threat against Means. But Dillard disagreed, arguing they were nothing more than an exercise of her First Amendment rights because the comments were not sufficiently specific to constitute a “true threat.” This summer, a federal judge agreed with Dillard and dismissed the claims against her ruling Dillard’s statements were constitutionally protected speech.

The appeal could give the federal appeals court an opportunity to clarify a murky area of First Amendment law, namely just when does threatening language become sufficiently dangerous to justify the government prohibiting it. But, it also sheds some light on the shift in tactics by anti-choice activists who are trying to stretch beyond recognition the scope of protections offered by the First Amendment. It’s too soon to tell just yet, but this case could prove to be an important test of the boundaries of the FACE Act and the First Amendment.

The notice of appeal was filed with the Tenth Circuit Court of Appeals Thursday, the AP reports.