Seventeen years ago this month, Justice Brett Kavanaugh was an attorney in the George W. Bush White House and Lee Boyd Malvo was earning the moniker "D.C. sniper" by helping his father figure John Allen Muhammad kill 10 people in and around the nation's capital.

By 2004, Muhammad was caught, convicted and sentenced to death; Malvo, 17 at the time of the shootings, was sentenced to life in prison without parole. Kavanaugh, meanwhile, was settling into his career as a D.C. Circuit judge — a stepping stone to his current seat at the high court.

Last week, the lives of America's newest justice and its most notorious juvenile killer converged in D.C., as Justice Kavanaugh listened to Malvo's attorney argue his life without parole sentence was unconstitutional. Justice Kavanaugh also listened to arguments for Virginia, the state appealing a lower court's decision that Malvo must be resentenced in light of several recent U.S. Supreme Court decisions that limited extreme punishments on youth.

And while other justices were also listening, no others talked nearly as much: in total, the Oct. 16 hearing's official transcript showed Justice Kavanaugh spoke 43 different times, nearly twice as often as the other justices.

"Kavanaugh was very engaged and clearly giving both sides of this case serious consideration," Ashley Nellis, a senior analyst for The Sentencing Project, told Law360. "It's hard to say how he's going to vote ultimately, but it was not at all evident that he was decided going in."

Along with President Donald Trump's other Supreme Court pick, Justice Neil Gorsuch, Justice Kavanaugh could be a critical vote in the case that hinges on how to interpret two landmark rulings that came down before he was appointed.

The first, 2012's Miller v. Alabama decision, found that — as its author, Justice Elena Kagan, put it at last week's arguments — "youth matters."

Drawing on brain science showing how juveniles are fundamentally different than adults, the Miller ruling held that mandatory life without parole sentences constitute cruel and unusual punishment when applied to juveniles.

"You have to consider youth in making these sorts of sentencing determinations," Justice Kagan said last week.

The court then made Miller retroactive in 2016's Montgomery v. Louisiana , requiring courts around the country to resentence an estimated 2,800 juvenile lifers so that their youth could be fairly considered. Montgomery also clarified that only those juveniles whose crimes reflected "permanent incorrigibility" could receive life without parole.

Since Miller, 17 states and D.C. have banned life without parole sentences for juveniles; others have carried out hundreds of resentencings or extended parole eligibility. But according to Malvo's attorney, WilmerHale partner Danielle Spinelli, there are still 60 teen lifers in six states who have not been resentenced or offered parole in accordance with Miller.

Malvo is one of them. After the conviction at the heart of last week's arguments, a jury considered whether he should be executed — death sentences were still allowed for juveniles at the time — or sentenced to life without parole. Jurors recommended the latter option and a judge issued the sentence.

Following Montgomery, Malvo sought a resentencing hearing on the grounds that his judge had not considered if his crimes reflected "irreparable corruption" or the "transient immaturity of youth" when she sentenced him.

In opposed his resentencing bid, Virginia has argued that Miller and Montgomery don't apply to him because his sentence wasn't technically "mandatory." Under Virginia law, judges can suspend a sentence, making it "discretionary," according to the state.

The federal government backed the commonwealth in the case and was represented by Eric J. Feigin, assistant to the solicitor general, during last week's hearing. Feigin argued that Miller and Montgomery only require "the opportunity to raise age as a reason for a lower sentence," not a "precise formula for taking age into account."

"You want us to hold that a discretionary regime satisfies Miller and Montgomery and remand for consideration of ... whether it was really discretionary [in Virginia]?" Justice Kavanaugh asked.

"That's correct, your honor," Feigin replied.

Questions of how discretionary Virginia's sentence "really was" dominated stretches of the hearing, with Feigin and Virginia Solicitor General Toby J. Heytens pointing to a related 2017 Virginia Supreme Court decision that held trial judges had the authority to suspend sentences "at the time of Malvo's trial."

"Malvo received a fair, lawful trial in which he presented significant evidence about his age," Virginia Attorney General Mark R. Herring said in a statement on the day of the arguments.

Justice Ruth Bader Ginsburg, however, noted that the only options at the time for his crime were death or life without parole. She also asked if any Virginia judge had ever actually reduced a juvenile life sentence.

"I'm not aware of an example," Heytens said.

Justice Kavanaugh focused less on whether Virginia's scheme was truly discretionary, instead focusing on how a discretionary life without parole sentence could be issued in accordance with Miller and Montgomery going forward.

"In 99.99% of these cases ... youth is raised by the defense counsel, and the sentencing judge either says nothing, just imposes the sentence without explaining anything about youth, or just discusses youth but says ultimately [she or he is] still going to stick with life without parole," Justice Kavanaugh asked Heytens. "So, in that circumstance, is that enough?"

Heytens said it was, and later, Justice Gorsuch took up a similar hypothetical question with Spinelli.

"So just all arguments are available and the district judge has to consider them — would that, in your mind, satisfy Miller and Montgomery?" he asked.

"I am not arguing that it would not," she answered. "We're only talking about the situation here, where there was no consideration of youth, not only with Malvo but all 13 of the people who are serving juvenile life without parole for capital murder in Virginia [and] were sentenced in exactly the same way."

The other Virginia teen lifers have more at stake in Malvo's case than he does: Now 34, Malvo is unlikely to ever get out, considering the fact that he has multiple life sentences in Virginia and Maryland and could still face murder charges in several other states where he's suspected of killing people. Still, a ruling in his favor could lead to resentencing hearings for the others.

A key focus in media coverage and amicus briefs in Malvo's case has been the impact resentencing could have on victims who thought their loved ones' killers were locked up for life. But aside from one mention during the Virginia solicitor general's opening remarks, victims' rights did not come up at last week's hearing.

Marsha Levick, a co-founder of the Juvenile Law Center who attended the arguments, said that while she's never been a victim of crime herself, she can still appreciate the pain that surviving family members go through when a resentencing hearing drags up traumatic memories.

"But can we prevent them having to do that by simply locking people up for the rest of their lives?" she added. "If the Constitution requires this parole eligibility for the vast majority of young offenders ... then we need to think about a better way we can help victims through this process."

In an emailed statement from a victims' advocacy group called the Criminal Justice Legal Foundation, attorney Kent Scheidegger did not mention the relatively low emphasis the justices gave victims' rights at the hearing. Instead, he echoed an argument that Feigin made by calling the Montgomery opinion a "dishonest representation of what Miller actually held."

"I'm sure Justice Kagan would like the court to just accept Montgomery's recasting of Miller on its face and endorse an intrusive rule for federal micromanagement of juvenile life without parole sentencing," he added. "I would be surprised if she has a majority for that."

The "recasting" reference is a challenge to certain language the Montgomery decision used in granting retroactivity to Miller's ban on juvenile life without parole sentences issued without consideration of youth.

Montgomery's author, Justice Anthony Kennedy, described Miller as a "substantive" ruling that "rendered life without parole an unconstitutional penalty for ... juvenile offenders whose crimes reflect the transient immaturity of youth."

But according to briefs supporting Virginia by Scheidegger's organization, the U.S., and a group of 15 states, Miller did nothing more than ban mandatory juvenile life without parole sentences — not require states to follow some new procedure for separating the irreparably corrupt juveniles who can be sentenced to life without parole from the transiently immature who can't.

Those contentions aside, Levick noted Montgomery was a 6-3 decision, with Chief Justice John Roberts siding with the majority just a few years after dissenting in the 5-4 Miller ruling.

"I don't think Montgomery can be overturned," she said.

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--Editing by Katherine Rautenberg.