At about 12.40pm on 2 January 1996, Timothy Jackson took a jacket from the Maison Blanche department store in New Orleans, draped it over his arm, and walked out of the store without paying for it. When he was accosted by a security guard, Jackson said: “I just needed another jacket, man.”

A few months later Jackson was convicted of shoplifting and sent to Angola prison in Louisiana. That was 16 years ago. Today he is still incarcerated in Angola, and will stay there for the rest of his natural life having been condemned to die in jail. All for the theft of a jacket, worth $159.

Jackson, 53, is one of 3,281 prisoners in America serving life sentences with no chance of parole for non-violent crimes. Some, like him, were given the most extreme punishment short of execution for shoplifting; one was condemned to die in prison for siphoning petrol from a truck; another for stealing tools from a tool shed; yet another for attempting to cash a stolen cheque.

“It has been very hard for me,” Jackson wrote to the American Civil Liberties Union (ACLU) as part of its new report on life without parole for non-violent offenders. “I know that for my crime I had to do some time, but a life sentence for a jacket value at $159. I have met people here whose crimes are a lot badder with way less time.”

Senior officials at Angola prison refused to allow the Guardian to speak to Jackson, on grounds that it might upset his victims – even though his crime was victim-less. But his sister Loretta Lumar did speak to the Guardian. She said that the last time she talked by phone with her brother he had expressed despair. “He told me, 'Sister, this has really broke my back. I'm ready to come out.'”

Lumar said that she found her brother's sentence incomprehensible. “This doesn't make sense to me. I know people who have killed people, and they get a lesser sentence. That doesn't make sense to me right there. You can take a life and get 15 or 16 years. He takes a jacket worth $159 and will stay in jail forever. He didn't kill the jacket!”

The ACLU's report, A Living Death, chronicles the thousands of lives ruined and families destroyed by the modern phenomenon of sentencing people to die behind bars for non-violent offences. It notes that contrary to the expectation that such a harsh penalty would be meted out only to the most serious offenders, people have been caught in this brutal trap for sometimes the most petty causes.

Ronald Washington, 48, is also serving life without parole in Angola, in his case for shoplifting two Michael Jordan jerseys from a Foot Action sportswear store in Shreveport, Louisiana, in 2004. Washington insisted at trial that the jerseys were reduced in a sale to $45 each – which meant that their combined value was below the $100 needed to classify the theft as a felony; the prosecution disagreed, claiming they were on sale for $60 each, thus surpassing the $100 felony minimum and opening him up to a sentence of life without parole.

“I felt as though somebody had just taken the life out of my body,” Washington wrote to the ACLU about the moment he learnt his fate. “I seriously felt rejected, neglected, stabbed right through my heart.”

He added: “It's a very lonely world, seems that nobody cares. You're never ever returning back into society. And whatever you had or established, its now useless, because you're being buried alive at slow pace.”

Louisiana, where both Washington and Jackson are held, is one of nine states where prisoners are serving life without parole sentences for non-violent offences (other states with high numbers are Alabama, Florida, Mississippi, Oklahoma and South Carolina). An overwhelming proportion of those sentences – as many as 98% in Louisiana – were mandatory: in other words judges had no discretion but to impose the swingeing penalties.

The warden of Angola prison, Burl Cain, has spoken out in forthright terms against a system that mandates punishment without any chance of rehabilitation. He told the ACLU: “It's ridiculous, because the name of our business is 'corrections' – to correct deviant behaviour. If I'm a successful warden and I do my job and we correct the deviant behaviour, then we should have a parole hearing. I need to keep predators in these big old prisons, not dying old men.”

The toll is not confined to the state level: most of those non-violent inmates held on life without parole sentences were given their punishments by the federal government. More than 2,000 of the 3,281 individuals tracked down on these sentences by the ACLU are being held in the federal system. Overall, the ACLU has calculated that taxpayers pay an additional $1.8bn to keep the prisoners locked up for the rest of their lives.

Timothy Jackson, in an old license photograph. Photograph: Jackson family Photograph: Jackson family

'It doesn't have to be this way'

Until the early 1970s, life without parole sentences were virtually unknown. But they exploded as part of what the ACLU calls America's “late-twentieth-century obsession with mass incarceration and extreme, inhumane penalties.”

The report's author Jennifer Turner states that today, the US is “virtually alone in its willingness to sentence non-violent offenders to die behind bars.” Life without parole for non-violent sentences has been ruled a violation of human rights by the European Court of Human Rights. The UK is one of only two countries in Europe that still metes out the penalty at all, and even then only in 49 cases of murder.

Even within America's starkly racially-charged penal system, the disparities in non-violent life without parole are stunning. About 65% of the prisoners identified nationwide by the ACLU are African American. In Louisiana, that proportion rises to 91%, including Jackson and Washington who are both black.

The US has the highest incarceration rate in the world, with 2.3 million people now in custody, with the war on drugs acting as the overriding push-factor. Of the prisoners serving life without parole for non-violent offences nationwide, the ACLU estimates that almost 80% were for drug-related crimes.

Again, the offences involved can be startlingly petty. Drug cases itemised in the report include a man sentenced to die in prison for having been found in possession of a crack pipe; an offender with a bottle cap that contained a trace of heroin that was too small to measure; a prisoner arrested with a trace amount of cocaine in their pocket too tiny to see with the naked eye; a man who acted as a go-between in a sale to an undercover police officer of marijuana – street value $10.

Drugs are present in the background of Timothy Jackson's case too. He was high when he went to the Maison Blanche store, and he says that as a result he shoplifted “without thinking”. Paradoxically, like many of the other prisoners on similar penalties, the first time he was offered drug treatment was after he had already been condemned to spend the rest of his life in jail.

The theft of the $159 jacket, taken in isolation, carries today a six-month jail term. It was combined at Jackson's sentencing hearing with his previous convictions – all for non-violent crimes including a robbery in which he took $216 – that brought him under Louisiana's brutal “four-strikes” law by which it became mandatory for him to be locked up and the key thrown away.

The ACLU concludes that it does not have to be this way – suitable alternatives are readily at hand, including shorter prison terms and the provision of drug treatment and mental health services. The organisation calls on Congress, the Obama administration and state legislatures to end the imposition of mandatory life without parole for non-violent offenders and to require re-sentencing hearings for all those already caught in this judicial black hole.

A few months after Timothy Jackson was put away for life, a Louisiana appeals court reviewed the case and found it “excessive”, “inappropriate” and “a prime example of an unjust result”. Describing Jackson as a “petty thief”, the court threw out the sentence.

The following year, in 1998, the state's supreme court gave a final ruling. “This sentence is constitutionally excessive in that it is grossly out of proportion to the seriousness of the offence,” concluded Judge Bernette Johnson. However, she found that the state's four strikes law that mandates life without parole could only be overturned in rare instances, and as a result she reinstated the sentence – putting Jackson back inside his cell until the day he dies.

“I am much older and I have learned a lot about myself,” Jackson wrote to the ACLU from that cell. “I am sorry for the crime that I did, and I am a changed man.”

Jackson expressed a hope that he would be granted his freedom when he was still young enough to make something of his life and “help others”. But, barring a reform of the law, the day of his release will never come.