New York Times

WASHINGTON — The day began with extended and sometimes wry reflections from Chief Justice John G. Roberts Jr. on the life and work of Justice Antonin Scalia, whose empty chair at the Supreme Court was draped in black. It ended with a liberal justice invoking events in Ferguson, Mo., and accusing a conservative colleague of being ignorant of facts in a case that could lead to “a police state.”

Justice Scalia’s death has upended the court’s work, withdrawing an important voice and often crucial vote from the contentious docket his remaining eight colleagues face in coming months in cases on abortion, immigration and religious freedom. It has also created a titanic struggle over who will succeed him, one that will play out in a divisive debate that found an echo Monday in the first arguments since Justice Scalia died on Feb. 13.

It did not take long for the justices, who arrived solemn and somber, to show their sharp divisions. In short order, rancor seemed to replace grief.

But first Chief Justice Roberts recalled his departed colleague.

“In 1976, during his tenure at the Justice Department, Justice Scalia argued his first and only Supreme Court case,” the chief justice said. “He prevailed, establishing a perfect record before the court.”

“Justice Scalia devoted nearly 30 years of his life to this court in service to the country he so loved,” Chief Justice Roberts continued. “He authored 282 majority opinions for the court. He was also known, on occasion, to dissent.”

“We remember his incisive intellect, his agile wit and his captivating prose,” the chief justice said. “But we cannot forget his irrepressible spirit. He was our man for all seasons, and we shall miss him beyond measure.”

Chief Justice Roberts paused. “And now,” he said, “we turn to the business of the court.”

The justices heard two arguments on Monday. The first, in a minor case on set-asides for businesses owned by veterans, had a muted tone, and the lawyers occasionally spoke at length without interruption, which is rare.

But before long, the usual rhythms re-established themselves. Justice Stephen G. Breyer drew laughter in the second half of the argument as he tried to puzzle out the position of a lawyer for the federal government, Zachary D. Tripp.

“Am I way off base or is that what you’re trying to say?” he asked. “And don’t just say it is because you think I’d agree with it, please.”

A few minutes later, there was more laughter as Chief Justice Roberts tried to make sure he had understood Mr. Tripp’s informal language correctly. “When you say you’re crushing the goals, that means you’re meeting them?” the chief justice asked.

The government had changed its position during the litigation, and now that the court has just eight members, finding ways to defer decisions may start to look attractive, particularly as finding common ground may prove challenging. So Justice Ruth Bader Ginsburg suggested that the Supreme Court ask a lower court to consider the new argument rather than itself deciding the case, Kingdomware Technologies v. United States, No. 14-916.

But the light and somewhat sleepy tone of the first argument vanished during the second one, in Utah v. Strieff, No. 14-1373. The justices, who had just spent several days together mourning a colleague, might have been expected to approach even a divisive case in a measured way.

But some of the exchanges were caustic and jarring.

The case arose from police surveillance of a house in Salt Lake City based on an anonymous tip of “narcotics activity” there. A police officer stopped Edward Strieff after he had left the house based on what the state later conceded was insufficient grounds, making the stop unlawful.

The officer then ran a check and discovered a warrant for a minor traffic violation. He arrested Mr. Strieff, searched him and found drugs. The question for the justices was whether the drugs must be suppressed given the unlawful stop or whether they could be used as evidence given the arrest warrant.

The court’s newest members, appointed by President Obama, were harshly critical of the officer’s conduct, invoking Ferguson and other communities in which police tactics have come in for criticism. President George W. Bush’s two appointees appeared prepared to excuse the stop as a misstep and not to second-guess the police more generally.

The divide seemed to illustrate how much is at stake in selecting Justice Scalia’s replacement.

Justice Sonia Sotomayor, an Obama appointee, said allowing searches like that of Mr. Strieff would be a dangerous step.

“What stops us from becoming a police state and just having the police stand on the corner down here and stop every person, ask them for identification, put it through and, if a warrant comes up, searching them?” she asked.

In Ferguson, she said, 80 percent of residents have warrants against them, mostly for traffic violations. (According to the Justice Department, about 16,000 of the city’s 21,000 residents are subject to arrest warrants.)

“There may be a very good incentive for just standing on the street corner in Ferguson and asking every citizen, give me your ID, let me see your name,” Justice Sotomayor said.

Justice Elena Kagan, also appointed by Mr. Obama, echoed that concern. “I was surprised beyond measure by how many people have arrest warrants outstanding, and particularly in the kind of areas in which these stops typically tend to take place,” she said. (New York City, for instance, has 1.2 million open warrants.)

Chief Justice Roberts, a Bush appointee, responded that numbers like those in Ferguson were not representative. “Obviously, you have, in particular communities, high numbers,” he said. “But some of them didn’t strike me — I was surprised how low they were: 323,000 is a big number, but that’s the entire state of Florida.”

Justice Samuel A. Alito Jr., also appointed by Mr. Bush, said there was no reason to suspect malfeasance. “Do you think the judges in the traffic courts are going to start issuing lots of warrants because they want to provide a basis for randomly stopping people?” he asked a lawyer for Mr. Strieff.

The lawyer, Joan C. Watt, started to answer, but Justice Sotomayor interrupted with an unusually personal rebuke. “I’m very surprised that Justice Alito doesn’t know that most of these warrants are automatic,” she said.

The court seemed headed for a 4-to-4 deadlock. Justice Scalia’s death had briefly united the court, but it took only hours for the old divisions to re-emerge, as sharp as ever.