Here’s a look at some major cases Brett Kavanaugh could help decide on the Supreme Court

Justice Brett Kavanaugh spoke on Monday. Manuel Balce Ceneta/Associated Press

And then there were nine.

Amid protests from the left and staunch cries of support from the right, Justice Brett Kavanaugh was confirmed to the US Supreme Court over the weekend and heard his first set of oral arguments Tuesday.

With the balance now tilted, 5-4, in favor of conservative justices, the Globe asked high court observers about cases they’re tracking in light of the new composition of the panel.

Kari E. Hong, a Boston College Law School professor, said she watched with interest Tuesday as the court heard arguments dealing with the Armed Career Criminal Act of 1984, which calls for stiffer sentences for crimes committed with firearms by offenders with three or more prior convictions for certain infractions.

“The majority of justices don’t like the law,” Hong said. “I don’t think Kavanaugh’s vote will make a difference, but it will be interesting to see if he still dissents.” That could be a harbinger of his more conservative opinions on criminal justice matters, she said.

Kavanaugh’s questions during Tuesday’s session, she said, “didn’t show a lot of empathy for the criminal defendant.”

Hong said in a follow-up e-mail that the career criminal act will remain on the books regardless of the outcome.

The “issue before the Court was not its constitutionality, but rather how to apply two of its provisions to a robbery and burglary statute,” Hong wrote. “Two of the justices mentioned that Congress has bills that would fix the problems that keep leading the [career criminal act] cases to come back to the Court with technical issues. It appears that the Justices will side with the defendants in that the broader interpretations of the law that would lead to longer sentences do not apply to them.”

Hong said she’s also watching a second case, Nielsen v. Preap, that was on the high court’s agenda Wednesday.

That case focuses on the question of whether “a criminal alien becomes exempt from mandatory detention” for deportation proceedings “if, after the alien is released from criminal custody, the Department of Homeland Security does not take him into immigration custody immediately,” according to a filing on the Supreme Court’s website.

Hong said she believes the Preap case will likely be a 5-4 decision, with Justice Neil Gorsuch and possibly Chief Justice John Roberts voting in favor of the immigrants.

“Kavanaugh will be with the dissent,” she wrote in an e-mail. “He expressed comfort [during oral arguments] with the government arresting someone on their death bed 50 years after a petty theft offense. That was the hypothetical given that Gorsuch and [Justice Stephen] Breyer felt would be too much power for the state to have. Kavanaugh defended that exercise of state power.”

Immigrant rights attorneys are representing lawful permanent residents who served time for criminal offenses and then “returned to their families and communities,” the lawyers said in an August brief. “Years later, the immigration authorities took them into custody and detained them without bond hearings.”

The lawyers contend their clients were held unlawfully because the “textual requirement that noncitizens be detained ‘when . . . released’ limits mandatory detention to those whom the [Homeland Security] Secretary detains ‘at the time of’ or ‘immediately’ upon their release.”

But the Department of Homeland Security has maintained in court filings that there’s no time limit for when it can take a convicted immigrant into custody following their release.

“What if the alien was sentenced to time served or released without a sentence of imprisonment, so the government could not have learned when he would be released until after that had occurred?” the solicitor general wrote for DHS in a brief last month. “What if the Department of Homeland Security (DHS) did not have officers available in the vicinity to effectuate the arrest? What if DHS asked the jurisdiction to notify it when the alien was going to be released, but the jurisdiction declined to do so?”

Daniel S. Medwed, a Northeastern Law professor who teaches courses on criminal procedure and evidence, said in an e-mail that he’s watching two cases in particular.

One is a Missouri death penalty case the court will hear in November.

“A man named [Russell] Bucklew claims that lethal gas would be better than lethal injection because of his underlying medical condition (Missouri permits both methods),” Medwed wrote. “I suspect and fear Kavanaugh will defer to the state’s discretion.”

A number of parties have filed amicus briefs in the case, including the ACLU, which is supporting Bucklew, and a consortium of death penalty states including Texas, Alabama, Arkansas and Colorado, that are backing the state of Missouri.

The ACLU brief says Bucklew, who killed a man in 1996 and raped the man’s girlfriend, then later escaped custody and attacked the rape victim’s mother with a hammer, would be subject to cruel and unusual punishment if executed by lethal injection.

The brief says Bucklew will “choke on his own blood and suffocate for four minutes before dying. This does not happen with other lethal injection executions. But Mr. Bucklew suffers from cavernous hemangioma, a rare medical condition that will lead to these results and make the lethal injection procedures particularly excruciating in his case.”

The death penalty states counter that if Bucklew prevails, the case could lead to “repeated and lengthy litigation and indefinite delay in carrying out death sentences. Prisoners would challenge each alternative method subsequently adopted by the State as lacking in some way due to the prisoner’s unique anatomy, history, or combination of conditions.”

A second case Medwed is following deals with the double jeopardy clause in criminal proceedings.

“[I]n December, the Court will hear a double jeopardy clause case that reconsiders the suitability of the so-called ‘separate sovereigns’ doctrine,” Medwed wrote. “That is, even though the 5th [Amendment] bans someone from being tried twice for the same offense, the Court has long recognized a ‘separate sovereigns’ exception — while, say, Massachusetts couldn’t try someone twice for murder for the same incident, the federal government could try the person after a Massachusetts state acquittal.”

Medwed said he believes a conservative “textualist” such as Kavanaugh, meaning a justice who believes legal statutes should be interpreted strictly as written, may “interpret the double jeopardy clause strictly to ban separate trials even in separate jurisdictions,” which could have implications for President Trump.

“In theory, [Trump] could pardon someone like [former national security adviser Michael] Flynn from a federal conviction down the road and states might be barred from prosecuting Flynn for crimes related to the same underlying event,” Medwed wrote.

Michael Waldman, president of the Brennan Center for Justice at NYU School of Law, said four justices have to agree to hear a case, so Kavanaugh’s placement on the court could affect the types of matters that are considered.

Among the test cases that could be accepted for review are those dealing with the Second Amendment, Waldman said, noting that Kavanaugh as an appellate judge dissented against a ruling upholding a state assault weapons ban.

Other upcoming cases deal with gerrymandering and whether the government can inquire about a person’s citizenship status on a census form, Waldman said by phone.

“We’re a few days into a new constitutional era,” said Waldman, a former speechwriting director in the Clinton administration. “If the court is aggressive and activist, it really will create a period of conflict” between the court and the broader public.