The Supreme Court ruled 7-1 in favor of Black Lives Matter activist DeRay Mckesson, blocking a lawsuit from a Louisiana police officer who was injured by a protester during a demonstration Mckesson organized.

Justice Clarence Thomas was the lone justice opposing the court's decision, and while he did not provide an opinion expressing his views, Mckesson was quick to criticize the conservative justice's opinion.

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"Clarence Thomas is just not on the right side of any of these issues," Mckesson tweeted Monday morning, roughly an hour after the court issued its ruling.

The police officer, identified in court documents as John Doe, sued Mckesson after an unidentified individual threw a hard object at him, striking him in the face. Doe suffered what the Supreme Court described as "devastating injuries" that included "loss of teeth and brain trauma."

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Doe sued Mckesson, claiming that he negligently held the protest in a way that led to his injuries. A federal district court dismissed the lawsuit, saying that Mckesson was protected by the First Amendment, but a Fifth Circuit Court of Appeals panel reversed, stating that because Mckesson's protest was already illegal because it obstructed a highway, the First Amendment did not protect him from civil tort claims based on events that stemmed from the protest. The appellate court also noted that because the protest blocked a highway, an encounter with police was foreseeable.

The Supreme Court ruled in an unsigned decision that the Fifth Circuit should not have interpreted the complex relevant tort law issues without looking into how the Louisiana Supreme Court addresses the relevant state laws.

"We think that the Fifth Circuit's interpretation of state law is too uncertain a premise on which to address the question presented," the Supreme Court said.

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New Justice Amy Coney Barrett was not involved in the court's decision. She participated in her first Supreme Court oral arguments Monday morning.