Ketanji Brown Jackson, the Supreme Court’s newest justice and the first Black woman to hold the position, proved one of the most active questioners on the bench Monday during her first argument at the High Court as the justices kicked off a new term.

Bedecked in the customary black robe, Jackson occupied a seat at the far end of the bench, in keeping with the court’s traditional seating arrangement based on seniority, with Chief Justice John Roberts at the center.

Jackson, a former judge on two lower federal courts in Washington, is expected to round out the court’s three-member liberal wing on a bench now dominated by six Republican-appointed justices pursuing an aggressive conservative legal agenda.

The court opened its term with a major environmental dispute over the federal government’s reach in protecting the nation’s waterways under the Clean Water Act.

Jackson took her turn among the justices in posing questions to the lawyers who argued the dispute between the Environmental Protection Agency and Idaho landowners. The landowners have urged the court to narrow the government’s authority over wetlands to encompass only those with a visible surface connection to U.S. waters.  

“You say the question is which wetlands are covered, which I agree with,” she told a lawyer for the property owners. “But I guess my question is, why would Congress draw the coverage line between abutting wetlands and neighboring wetlands when the objective of the statute is to ensure the chemical, physical and biological integrity of the nation’s waters?”

The tenor of Jackson’s questions hewed closely to the purpose of the Clean Water Act, which turns 50 this month, and the underlying facts of the dispute.

As the court’s only former public defender, Jackson is expected to bring a unique perspective to her new role, though she will not fundamentally alter the court’s conservative tilt. 

She fills the seat vacated by Justice Stephen Breyer, for whom she once clerked, following his retirement this summer and a grueling Senate confirmation process earlier this year. 

Jackson, responding to a question during her Senate confirmation hearing in March, said her judicial methodology cannot be easily defined — a sharp departure from the Supreme Court confirmation of Justice Amy Coney Barrett, who labeled herself an “originalist” who would approach the task “in the mold of Justice Scalia.”

Shying away from “a particular label” to define her style, Jackson said she adheres to a methodology that begins with assuming a position of neutrality, proceeds with various interpretive tools toward a transparent ruling “without fear or favor,” and studiously abides by judicial constraints.