The Supreme Court on Wednesday seemed prepared to reinstate the death penalty for Boston Marathon bomber Dzhokhar Tsarnaev, despite aggressive questioning from the court’s liberals about whether crucial evidence was kept from jurors who decided not to spare his life.

The court was reviewing a decision by a three-judge panel of the U.S. Court of Appeals for the 1st Circuit. In July, the panel agreed with Tsarnaev’s lawyers that the judge overseeing his 2015 trial did not adequately question potential jurors for bias in the case, which received massive publicity.

In overturning Tsarnaev’s death sentence, the panel also said some evidence was improperly withheld that might have indicated his older brother, Tamerlan, was more culpable for the bombing. Tamerlan Tsarnaev was killed as police closed in on the brothers days after the April 2013 attack.

Dzhokhar Tsarnaev’s guilt was not at issue in Wednesday’s hearing. He was convicted in the deaths of a graduate student from China, Lingzi Lu, a restaurant manager named Krystle Campbell, and 8-year-old Martin Richard of Boston. The only question was whether he should be sentenced to life in prison or put to death.

The case created a dilemma for the Justice Department, which had asked the Supreme Court to reverse the appeals court decision even though President Biden has halted federal executions and opposes the death penalty.

That prompted Justice Amy Coney Barrett to ask Justice Department lawyer Eric Feigin about the administration’s “end game.”

If the court agrees to reinstate the sentence, she said, “presumably, that means that he is relegated to living under the threat of a death sentence that the government doesn’t plan to carry out. So I’m just having trouble following the point.” Tsarnaev, 19 at the time of the attack and now 28, is imprisoned in Colorado.

Feigin said there would be time for the administration to consider clemency or other issues in Tsarnaev’s case, but that the point was to reinstate a sentence that was justified.

“What we are asking here is that the sound judgment of 12 of [Tsarnaev’s] peers that he warrants capital punishment for his personal acts in murdering and maiming scores of innocents, and along with his brother, hundreds of innocents at the finish line of the Boston Marathon, should be respected,” he said.

The appeals court said U.S. District Judge George A. O’Toole Jr. erred in two ways during Tsarnaev’s complicated and high-profile trial: there should have been more detailed questioning of potential jurors about what opinions they had formed because of the massive publicity about the act of terrorism, and Tsarnaev’s lawyers should have been allowed to tell jurors deciding his fate that the older brother had been tied to a 2011 triple slaying in Waltham, Mass.

It is the latter issue that took up much of the court’s 90-minute hearing, with conservative justices questioning the relevance of the elder Tsarnaev’s alleged role in the triple slaying and liberal justices noting that it was crucial to the defense’s point that the younger Tsarnaev was unduly influenced by his brother.

Said Tsarnaev’s lawyer at the Supreme Court, Ginger D. Anders: “The theory is that Tamerlan influenced Dzhokhar, indoctrinated Dzhokhar, and Dzhokhar radicalized because of Tamerlan, and Tamerlan was more likely to have led the bombings. I think Tamerlan’s commission of a previous jihadist murder was directly relevant to that theory.”

Tamerlan Tsarnaev was implicated in those killings after the bombing and after his death. Ibragim Todashev said the elder Tsarnaev had recruited him to rob three men in 2011. After the men were bound, Todashev said, Tsarnaev slashed their throats.

But as Todashev was being interrogated, he charged toward investigators and they shot and killed him.

Justices Samuel A. Alito Jr. and Brett M. Kavanaugh wondered how such speculative evidence could have convinced jurors that the younger Tsarnaev was less culpable for setting a bomb in a terrorist attack several years later.

“We don’t know what happened,” Kavanaugh said. “Todashev had all the motive in the world to point the finger at the dead guy.”

But Justice Elena Kagan led the liberal justices in saying that during the death penalty phase of a trial, the judge should have been more accommodating of Tsarnaev’s defense.

“Whether because of the brother’s age, size, aggressiveness, domineering personality, traditional authority as the eldest brother or other reasons, the defendant was particularly susceptible to his older brother’s influence,” Kagan said, recounting Tsarnaev’s presentation at the sentencing phase. “The defendant’s brother planned, led and directed the bombing. The defendant wouldn’t have committed the crimes but for his older brother. . . . That was the entire case.”

She continued: “And yet, the court keeps out evidence that the older brother committed three murders?”

Anders told the court: “The Waltham evidence would have changed the terms of the debate.”

Chief Justice John G. Roberts Jr. was among the justices advocating deference. “Assuming it would change the terms of the debate, it would focus debate on something that the district court determined really just couldn’t be resolved,” Roberts said.

Feigin told the court it could put all of that aside, and determine that if there was error on the judge’s part, it is not the kind of error that would result in the jury finding Dzhokhar Tsarnaev deserved anything less than death.

In a style more like a lawyer making a closing argument to a jury, Feigin told the justices to watch video of Tsarnaev placing his backpack containing a bomb near a group of children at the race’s finish line. Feigin said the younger brother was the one to give a signal to set off the first explosion.

And while the brothers were on the run, they killed a campus security guard and committed a carjacking. They threw pipe bombs during the shootout with law enforcement. And then Tsarnaev hid “in someone’s backyard in a boat, where he writes a manifesto justifying his jihadist acts,” Feigin said.

“The jury’s nuanced verdict in this case was based on that evidence, not anything about pretrial publicity or anything about Waltham,” Feigin said.

The case is U.S. v. Tsarnaev.