WASHINGTON - Marsha Levick, cofounder of the Juvenile Law Center in Center City, greeted a crush of reporters outside the U.S. Supreme Court on Tuesday morning with hope - and a shrug.

She was there for arguments in Montgomery v. Louisiana, a case that could determine whether 500 Pennsylvania inmates - those who were sentenced as juveniles to life without possibility of parole - will die in prison or have a chance at release. It could go either way, Levick said.

The court ruled in 2012 in Miller v. Alabama that automatic life-without-parole sentencing guidelines for juveniles were cruel and unusual and violated the Eighth Amendment. Ten states applied that retroactively; others, including Pennsylvania, did not. The Montgomery case could determine whether Miller will offer relief for inmates whose convictions are final.

The arguments focused heavily on whether the court even had authority to hear the case. Still, Levick, cocounsel for Henry Montgomery, convicted of a fatal shooting at age 17 in 1963, was cautiously optimistic.

"The justices were concerned about jurisdiction," she told reporters. "But there seemed to be a strong sentiment among several justices that there is something inherently wrong about not applying an Eighth Amendment rule retroactively."

Then, Levick and a couple dozen colleagues and supporters piled into a bus bound for Philadelphia, hoping to make it through I-95 traffic in time for their 40th anniversary gala, which had been planned long before the court scheduled its arguments.

It was a hectic but fitting way for the Juvenile Law Center to mark four decades of helping transform the way the American legal system treats children.

Founded on a shoestring by four new Temple Law graduates in 1975, JLC has been involved in a string of Supreme Court cases that have rolled back some of the harshest sentences for juveniles across the country. The firm has also worked on statewide juvenile-justice and child welfare reforms, and it's taken on some of the most troubling cases around the region, including the "Kids for Cash" scandal in Luzerne County and harsh solitary confinement practices in New Jersey.

"They've been at the forefront of every major juvenile justice issue for decades," said Wallace Mlyniec, senior counsel and former director of Georgetown's Juvenile Justice Clinic. "You see their fingerprints everywhere - not just in Pennsylvania, where they have done wonders for children all throughout the state. They've replicated a lot of that work throughout the country."

JLC was the first nonprofit public-interest law center focused on children in the country when it started out in borrowed space in a cardiologist's office.

The timing was right.

"We helped create a field," said Bob Schwartz, executive director of the law center.

The Supreme Court had only recently, in 1967, ruled that kids, like adults, had a right to counsel in delinquency proceedings, and legal services organizations hadn't caught up. The Defender Association of Philadelphia didn't yet have a child advocate unit.

Funding was a challenge. "In our first seven years, we ran out of money three times and went on unemployment," Schwartz said.

But the need was there: JLC was flooded with referrals, from Philadelphia and around the country.

At first, it tried to make a difference one kid at a time. Later, it refocused on systemic change. That includes pushing back against the harshest punishments for juvenile offenders - filing briefs in cases that led to bans on the juvenile death penalty and juvenile life without parole in non-homicide cases.

And, in 2012, it filed a brief in Miller v. Alabama. When Montgomery came up, it contacted the lead attorney to offer support once again. Instead, it was asked to serve as cocounsel.

Most of the 500 Pennsylvania lifers affected, including 292 from Philadelphia, have filed motions seeking relief under Miller, and all of those are still waiting.

At Graterford state prison, dozens of men sentenced to life for murders they committed as teenagers are watching the Montgomery case anxiously, said Jorge Cintron Jr., a lifer 20 years into his sentence.

He doesn't hold out hope for commutation, as only six life sentences have been commuted during his time in prison. But many of the men haven't given up, he said, educating themselves and seeking entry into training programs, many of which are closed to lifers.

Cintron is in school to be a barber: His dream, if the courts grant him a second chance, is to start a school where he can train kids in haircutting who would otherwise be dealing drugs.

Whatever the decision in Montgomery, more cases are in the pipeline. One of those, Levick hopes, could end mandatory sentencing for kids for good.

In the meantime, there is still work to be done on the local level.

One of the most notable cases JLC took on in Pennsylvania began with a phone call from Laurene Transue in 2007. Her 15-year-old daughter, who had no record, had been sent to juvenile placement for creating an insulting MySpace page.

Transue, of White Haven, Pa., contacted every government and nonprofit agency she could think of.

"Everyone else I called said, 'There's no hope. Your kid's in the system, and that's the way it's going to be,' " Transue said. "JLC gave me hope."

Transue's daughter, Hillary, was the first of 2,400 kids JLC has helped overcome unfair sentences in Luzerne County, where judges were taking kickbacks to send juveniles to a private placement facility.

And, in 2010, when Sandra Simkins, director of Rutgers University's Children's Justice Clinic, discovered that New Jersey juvenile facilities were holding kids in solitary confinement for weeks at a time, she also looked to JLC. She contacted it after meeting Troy, a 16-year-old who had been in solitary for more than six months and who was covered in self-mutilation scars.

"When we found Troy, Marsha's the one I called. She's the one everyone calls," Simkins said. With pro bono help from Dechert L.L.P., JLC won a $400,000 settlement for Troy and another child. The settlement helped draw so much attention that, in August, New Jersey enacted a series of juvenile justice reforms, including drastically reduced limits on solitary confinement.

It's one of many victories JLC was celebrating at the Hyatt at the Bellevue on Tuesday night. The event was also a sort of retirement party for Schwartz, who is stepping down.

Under JLC's new leader, Susan Mangold, the firm will continue to seek juvenile-justice reforms, to push for an end to juvenile solitary confinement, demand better protection for juvenile records, and advocate for child welfare reforms.

"There's a mind-set about how we charge people, how we punish people, and what we do when they come out. Right now, it's more forgiving than it has been in decades," Levick said. "We see one of our jobs here as frankly to maximize this moment."