WASHINGTON — It was solemn, dignified and brief — the antithesis of the prolonged, bitter, circuslike spectacle that preceded it. Yet when the Supreme Court formally welcomed Brett M. Kavanaugh as an associate justice on Thursday, there were still echoes of the rancor his nomination to the court ignited.

Justice Kavanaugh skipped the most public element of the ceremony, a traditional walk down the court’s front steps with Chief Justice John G. Roberts Jr., “out of an abundance of caution, due to security concerns,” according to a spokeswoman for the court, Kathleen Arberg.

Inside the majestic chamber, where members of Washington’s Republican establishment mingled amid the marble columns before the investiture began, there were reminders not just of the contentious confirmation process but also of the turmoil on the Trump legal team, which deepened this week after President Trump fired Attorney General Jeff Sessions.

Around Justice Kavanaugh was a vivid tableau of Mr. Trump’s Washington, a city rived by the battle over the Supreme Court and shadowed by questions about the rule of law. For about 15 minutes, many of the key players were gathered in the same room.