WASHINGTON • During a break in a basketball game to raise money for charity, Mr Shon Hopwood told some of his Georgetown law students it felt different than the last time he was on a court.

When he played basketball in federal prison, he had to carry a shank, a makeshift knife, in case his team started to lose.

His students laughed. He ran back onto the law school court - and sank the winning shot.

Mr Hopwood's new job as a tenure-track faculty member at the Georgetown University Law Centre is only the latest improbable twist in a remarkable life.

In the last 20 years, he has robbed banks in small towns in Nebraska, spent 11 years in federal prison, written a legal petition for a fellow inmate so incisive that the US Supreme Court agreed to hear the case, earned undergraduate and law degrees and competitive clerkships, written a book, married his home- town crush and started a family.

But this could be his most compelling role yet. His time in prison gave him a searing understanding of the impact of sentencing and the dramatic growth in incarceration in the US, an unusual perspective on the law that allows him to see things other lawyers overlook. And he takes the job at a time when criminal justice issues have real urgency, from lawmakers to protesters and students.

"It's one of the big social justice issues of our time," he said.

The United States has 5 per cent of the world's population but 25 per cent of its prisoners.

"Between prison, jail, home confinement, probation, parole, combined it's about 10 million people. It's a big number." And almost three-quarters of those released are back in custody five years later. He hopes to change some of that.

"The story's still writing itself," he said in his office recently, marvelling while students hurried to class. "I feel like I'm living someone else's life quite often these days."

Mr Hopwood's life didn't start out as remarkable. It began with a happy childhood in a town of 2,500 people in Nebraska. His dad managed a cattle feed yard and his parents helped found a church. He was friendly and well-liked, uninterested in school, and best known for his skill on the basketball court.

An athletic scholarship to college ended when he got kicked out for skipping class. After two years in the US Navy, he drifted back to Nebraska, depressed, drinking, doing drugs, living in his parents' basement and working 12-hour shifts on a cattle farm, shovelling manure.

One night his best friend suggested that they rob a bank.

In August 1997, Mr Hopwood walked into a bank, sweating, heart racing, dropped a metal toolbox to the floor with a bang and pulled a rifle from his coveralls. With the terrified customers and tellers locked into a vault he sped away with US$50,000 of other people's money and his friend, who knew every bit as well as he did that what they had done was horribly wrong.

His friend suggested sending the money back, with a note. Instead, Mr Hopwood went on to rob four more banks.

At his sentencing, 30 family members stood behind him, most of them crying. He was 23 years old. Judge Richard Kopf thought he was a punk. When Mr Hopwood said he was going to turn his life around, Mr Kopf said something disdainful like: "I guess we'll see in about 13 years."

His first morning in federal prison, Mr Hopwood got up early to work out and watched as two inmates yanked another one from a pull-up bar, knocked him to the ground and stomped on the man with steel-toe boots, leaving bits of teeth in pools of blood.

Working in the prison law library sounded like a good idea. At first, he just checked books out. But in the summer of 2000, a Supreme Court decision caught inmates' attention. Essentially, Mr Hopwood explained, "things that can increase your sentence need to be proven to a jury, or you need to plead guilty to them". He had been sentenced based on guidelines for armed robbery, even though he had pleaded guilty to unarmed robbery.

A technicality, maybe, but he began dreaming of getting out early. Among all the other reasons to leave, he had begun a friendship, by mail, with a girl from back home.

After two months of research, he mailed off a brief and quickly got a response: He had filed it to the wrong court. And when he redirected his appeal, Judge Kopf denied it; the new decision did not apply retroactively in his case.

Still, something had clicked. Trying to figure out a solution to the legal puzzle was the first academic thing Mr Hopwood had ever enjoyed. It came easy too. Soon he was sending memos to other inmates' lawyers, suggesting strategies. Then he was writing briefs.

He was finding errors, often from overworked public defenders, like a young black man sentenced to 161/2 years for possessing less than a handful of crack cocaine because he had mistakenly been labelled a career offender. With Mr Hopwood's help, the man's sentence was reduced by more than 10 years.

The third brief he ever wrote was for a friend whose appeal had been denied. Mr Hopwood spent months learning about the Supreme Court and habeas petitions, and one night he realised how he could frame an argument using the Sixth Amendment rather than the Fifth. After many drafts, honed by conversations with fellow inmates that forced him to distil the legal issues into simple, compelling logic, he typed out a petition for certiorari and mailed it off.

Months later, he was working out when a prisoner came running towards him, screaming that Mr Hopwood was going to die. He tensed for a fight; he had recently survived a situation in which he fully expected to be stabbed to death by gang members. But the man was holding a newspaper, with the story of the Supreme Court accepting a petition from a federal prisoner.

The odds of that happening are maybe one in 10,000, said Mr Seth Waxman, the former US solicitor- general who agreed to argue the case for free. He read the petition with amazement. "It was incredibly good. It really identified, in sort of a crystalline form, the questions presented. It explained the conflict, it explained the importance." He immediately wanted to talk to the bank robber who could write such a thing, and thus began a friendship that would help change the trajectory of Mr Hopwood's life.

Soon he was spending his time doing things like reading a 1,650-page textbook on criminal procedure. Twice. And with new sentencing guidelines, he was busy churning out work for other inmates.

"I was running a law firm in prison," he said lightly. Because he was now convinced that sentences beyond about five years didn't make sense for any but the most dangerous criminals, because he was upset by the disparities in sentences, because he saw prison more often hardening people or cutting off their chances for reform than turning their lives around, he enjoyed seeing people packing for home. He had another petition granted by the Supreme Court.

When he walked out of prison in October 2008, he was 33 and overwhelmed with anxiety about rebuilding his life. He knew no one was clamouring to hire felons. He wanted to get married and go to college, and he had no money. He was working at a carwash when he had another moment of grace: A family-run legal printing business in Omaha agreed, after getting some reassurance from Mr Waxman, to hire him to help with their Supreme Court briefs. "If that doesn't happen, none of this does," he said.

A story in The New York Times unleashed a flood of invitations to speak, and a book deal. Still it was difficult, given his resume, to get into law school. But the University of Washington granted him a full scholarship that made it possible - even with a little boy at home, and a girl born on the first day of law school - to attend.

He startled his former probation officer at the courthouse two months after his supervised release ended. He was not there for his mandatory check-in. He was arriving for work, clerking for a federal judge.

As he studied 12 hours a day, he wondered: Would he be granted a law licence at the end of all this, or would they reject him because of his criminal record? The hearing was long, but in the end, the vote was unanimous. And in April 2015, after he passed the bar exam, he was sworn in as a lawyer by the DC Circuit judge who had chosen him for a prestigious clerkship.

He joined Georgetown on a teaching fellowship about a year ago. He sees issues others don't, strategies that others don't, said director of appellate litigation Steven Goldblatt. "He understands the problems of incarceration in a way that somebody who just studies them as an academic is not able to get," said Dr William Treanor, the law school's dean.

Colleagues were struck by his academic writing, Professor Goldblatt said, in which Mr Hopwood wrote about the rule of lenity, which he described as designed to protect citizens from getting caught in vague laws, and argued it must be revitalised to push Congress to write with more precision when drafting laws that take away liberty.

It's not a theoretical issue, Prof Goldblatt said. It's fundamental. "Why wasn't there more written about it? Damned if I know."

The surreal moments continue. Recently, Mr Hopwood helped his former defence attorney practise a case to be argued in front of the Supreme Court. He also spoke on an academic panel with Mr Kopf. It was an emotional meeting.

The judge gave Mr Hopwood a gift that had great meaning for him - a leather briefcase Mr Kopf had received from a former prisoner whom he had defended. It was a recognition, Mr Kopf said, that he and Mr Hopwood were both trying to emulate justice.

"I don't know if it was atonement as much as it was, 'Carry on - keep doing what you're doing,'" Mr Kopf said, thinking out loud. "I would do anything for Shon."

Mr Hopwood is still, at 41, haunted by guilt and regret for his crimes. But he is an optimist, and he has accepted that he can only change the future. Now his primary goal is to help people, whether by serving as a reminder that you can turn your life around, by giving students an understanding of the real impact of the law, or, he hopes, by influencing the criminal justice system.

So while he kept the letter from a law firm offering him US$400,000 (S$560,00) a year, it was just as a curiosity. The money would be nice, but influence is what he wants. The Capitol dome is literally in view from campus, and most days he walks right past the Federal Bureau of Prisons.

Even now, preparing to start a new post at Georgetown on July 1 as an associate professor of law, he doesn't feel like he's made it.

"I'll feel that way when the federal government passes a Bill that gets rid of federal mandatory sentences," he said. "That will be the moment for me."

WASHINGTON POST