MINNEAPOLIS -- Chief Justice John Roberts for the first time Tuesday addressed the recent bitter partisan fight over new Justice Brett Kavanaugh and the Supreme Court, seeking to "assure" an audience that the court will serve "one nation" and not "one party or one interest."

Before being interviewed by a law professor at the University of Minnesota, Roberts said he needed to speak to the "contentious events in Washington in recent weeks," and to "emphasize how the judicial branch is, must be, very different."

"I have great respect for our public officials; after all, they speak for the people, and that commands a certain degree of humility from those of us in the judicial branch, who do not.

"We do not speak for the people, but we speak for the Constitution."

The nasty fight over Kavanaugh's confirmation and his replacement of Justice Anthony Kennedy is likely to solidify a conservative majority on the Supreme Court for a generation. It now has five consistent conservatives, all chosen by Republican presidents, and four liberals picked by Democratic presidents.

But Roberts said the court intends to put that aside.

"Our role is very clear: We are to interpret the Constitution and laws of the United States, and to ensure that the political branches act within them," he said. "That job obviously requires independence from the political branches. The story of the Supreme Court would be very different without that sort of independence."

Justices don't react to polls, Roberts said later in his comments, and he said some of the great decisions of the court - Brown v. Board of Education, or West Virginia v. Barnett, which said government could not compel students to salute the flag in violation of their religious beliefs - came in cases where the court was protecting minorities from the will of the majority.

Other justices have made similar defenses of the court, or made symbolic gestures of unity. Both liberal and conservative justices showed up for Kavanaugh's hastily scheduled swearing in after he was approved in one of the closest votes in history. All justices attended a later White House ceremony.

Roberts did not mention Kavanaugh specifically, but gave him a nod of approval by quoting him.

The 63-year-old chief justice noted that for a century, justices have shaken each other's hands before taking the bench to hear arguments.

"It's a small thing, perhaps, but it is a repeated reminder that, as our newest colleague put it, we do not sit on opposite sides of an aisle, we do not caucus in separate rooms, we do not serve one party or one interest, we serve one nation."

He added: "And I want to assure all of you that we will continue to do that."