Eighteen months after Michelle Carter was convicted by Judge Lawrence Moniz in Bristol County for involuntary manslaughter for the death of her boyfriend Conrad Roy, who killed himself in 2014, she’ll begin serving a 15-month sentence.

After Roy was found dead in his car after having filled it with toxic gas, the juvenile court said Carter had a duty to call the police to prevent Roy’s death. Instead, she encouraged him to stay in his car, and other texts show Carter encouraging Roy to take his own life.

“You’re just making it harder on yourself by pushing it off, you just have to do it,” Carter wrote in one message. “You’re ready and prepared. All you have to do is turn on the generator and you bee free and happy. No more pushing it off, no more waiting,” she wrote in another.

On Monday, the state’s highest court upheld Moniz’s conviction, and Carter’s lawyers say they plan on taking the case to the Supreme Court. The case has been debated amongst legal scholars and advocates, with some saying the case sets a dangerous precedent that could criminalize speech that would normally not be considered manslaughter.

“If you were to say that words are purely coercive, it could in fact threaten end of life discussions between people and their loved ones,” Carol Rose, Executive Director of the ACLU Massachusetts told Boston Public Radio on Tuesday. “It could in fact be applied to situations where teenagers say reckless things like, ‘Hey, pop-a-wheelie,’ or, ‘Hey, let’s jump off that bridge.’”

Read more: How Likely Is The Michelle Carter Case To Reach The Supreme Court?

Rose said that while the case was “indisputably a tragic situation,” the court made a new precedent by saying speech in and of itself can be considered grounds for a criminal indictment. Previously, Rose said, for speech to be considered criminal it needed to be linked with another action, such as a bank robber threatening to use a gun, but not actually firing it. According to Rose, the robber’s words imply the use of force, but in Carter’s situation there was not an actual criminal action linked to her speech.

“[The court] didn’t find that there was any action other than the words alone, so it’s a circular reasoning for the court to say, ‘There was nothing other than the speech, but it was speech incident to criminal conduct, which itself was then criminal conduct,'” Rose said.

In the view of the Supreme Judicial Court, however, Carter’s failure to alert authorities to Roy’s suicide was sufficient grounds for a guilty verdict.

“After she convinced him to get back into the carbon monoxide filled truck, she did absolutely nothing to help him: she did not call for help or tell him to get out of the truck as she listened to him choke and die,” Justice Scott Kafker wrote in the court’s opinion.

Rose understands that a guilty verdict might appear to be the “common sense” outcome for this case, but is now concerned that the ruling will set a precedent which could result in negative outcomes the SJC may not have considered in its decision.

“These are really hard facts. These are really tragic facts that common sense would lead us to say, ‘Oh my goodness, we have to find a way to punish,’ but our concern is that the actual reasoning here opens the door to potential applications in contexts that we as a society don’t want it to be applied,” Rose said.