A North Carolina Supreme Court justice has filed a federal lawsuit against the state’s judicial standards commission after the body opened an investigation into comments she made about the diversity of the state’s judicial system, court documents show.

Anita Earls, who is one of two Black justices on the state’s highest court, argued in the lawsuit that her comments on diversity are protected as political speech under the First Amendment.

The North Carolina Judicial Standards Commission launched its latest investigation into Earls after she told the online legal journal Law360.com that the state supreme court should examine the reasons behind the lack of diversity in state courts and what implicit biases may be within the judiciary.