Most of the time, tolerant, moderate people find it difficult to understand why anyone should object to the presumption of innocence, that central thread of our justice system. It's a powerful tool of justice: that a citizen stands free and innocent until found guilty beyond reasonable doubt by a jury of his or her fellow citizens.
It lends dignity to a country's code: not all democracies operate such a system. We inherited it from Britain, which also passed it to the burgeoning American colonies. Personally speaking, I'm almost fanatically devoted to it. Just as I believe almost fanatically that our judiciary must be detached and objective.
The principle of judges being seen to be scrupulous as well as actually behaving with scrupulous correctness in law caused the Court of Criminal Appeal to overturn a life sentence handed down in 2008 in the Central Criminal Court by Mr Justice Paul Carney. Two men were before him charged with the murder of a man called Christy Cawley, whom they had chased into the flats complex where he lived in Inchicore in Dublin. Mr Cawley was stabbed six times.
One of the stab wounds severed an artery in his left thigh, and he bled to death within minutes, watched by his wife and three of his children, one of them five years old. The other attacker had "merely" beaten the victim with a hurley.
During the period in which the trial was taking place, Mr Justice Carney gave a lecture in a university in which he referred to the ugly prevalence of knife crime and subsequent fatalities in our society, and was also critical of some aspects of sentencing policy. When the jury delivered its verdict, Mr Justice Carney sentenced both murderers to life imprisonment.
As was their right, they appealed the sentence, and the Court of Criminal Appeal found in their favour, deeming the conviction "unsafe" due to Mr Justice Carney's entirely separate lecture.
That was three years ago. Last Tuesday, the re-trial ordered by the Court of Criminal Appeal was completed. The two men were once again found guilty -- one of them, the man who wielded the knife, by a unanimous verdict; the other, who had used the hurley to beat their victim, by a 10 to two verdict. Once again, both murderers received life sentences, this time from Mr Justice Paul Butler. And in sentencing them, Mr Justice Butler said categorically he "echoed" Mr Justice Carney's concerns. The difference was he didn't say it during the course of the trial. And that is what is meant by the judiciary being seen to be scrupulous as well as being scrupulous.
The two men who were sent down on Tuesday were brothers, Jeffrey and Warren Dumbrell. Jeffrey, who wielded the knife, is 30, his brother Warren 36.
Jeffrey and Warren Dumbrell are two of nine siblings. Their father, Colin Dumbrell, gave an interview in 2005, in which he said: "I've been a criminal all my life. I came from a wealthy family so I didn't need to turn to crime. But I chose to and I'm not ashamed of it. I've done bank robberies and armed robberies and I don't give a shit what people think of me."
One son, Leroy, was at the centre of a walk-out by prison officers only a year ago: incarcerated in Castlerea Prison, he was moved to the separation unit in Mountjoy; but he was deemed by prison officers to be so dangerous that they were not happy with the arrangements for his supervision, and downed tools.
Leroy, 25, is described as the most dangerous and disruptive prisoner in the system and a massive danger to the public when at large. In 2002, then a teenager, he was one of three youths who tortured a middle-aged woman in her home in south Dublin, setting her clothes alight, then pouring boiling hot water over her during an aggravated burglary. While all three were quickly identified and arrested by gardai, they were granted bail.
While at large in 2004, Leroy carried out an unprovoked attack on a man walking his dog. The victim was severely and permanently injured, including partial sight loss. Leroy has been disciplined 59 times since being imprisoned in 2006, mostly being sent to solitary confinement. He was the ringleader of a recent riot in Mountjoy Prison in which one officer had his face badly slashed with a blade.
Tommy Dumbrell, 26, is an addict with 29 convictions for drugs, traffic and other offences. He featured in newspaper reports in June 2009 when he caused an explosion and set himself on fire after he lit a cigarette while sniffing aerosol in a flat in Inchicore.
Another brother, Leonard, 21, has amassed 103 convictions since 2002.
When Warren and Jeffrey Dumbrell walked back into Mountjoy in handcuffs on Tuesday evening, they were in familiar territory, too. They had pleaded not guilty to the murder of Christy Cawley, as was their right, and they had been defended by senior counsel, as was their right. For, until the jury brought in its verdict, in this re-trial as well as the original trial, they were innocent men.
But Jeffrey Dumbrell, the man who slashed open Christy Cawley's body in six places (which he admitted, although denying murder . . . the fatal wound was seven inches long) already had eight convictions which had resulted in jail sentences. Eight.
Warren, the older brother, is a familiar name to those involved in the legal and judicial systems. Last week's conviction for murder was his 27th conviction; his crimes have included assault, robbery, burglary, and possession of firearms. He was 13 years old when first convicted for burglary, probably at that time merely an unnoticed youngster in the Children's Court whom officials and lawyers alike might have felt a pang for, as they worried that he might be set on the wrong road.
Ten years later, he had gone down that road: he was in Mountjoy, head of a prison gang that held five officers hostage in 1997. Warren Dumbrell held a blood-filled syringe to the throat of one of the officers, telling him he had had "the virus" since he was 15 years old. He'd make the officer "drink his blood," he said.
So how did these two violent, dangerous men come to want to kill Christy Cawley? Their brother Tommy had gotten into a row with Cawley on a bus in 2006. A challenge was thrown down for a fight that evening, to take place behind the flats where he lived.
Tommy Dumbrell never turned up. Instead, Warren and Jeffrey arrived, Jeffrey with a knife; Warren with a hurley. Christy Cawley was terrified and took flight to go back home. He was chased, and caught in the stairwell. His wife Janette was looking down the stairs, so were two of his children, his 16-year-old daughter, and even more horribly, his five-year-old son.
The little boy, his mother told the court during the Dumbrells' trial, became mute for three months after he watched his father being butchered.
The family of Christy Cawley endured five years of attacks and threats, including a pipe bomb attack and an attempt to burn them alive as they slept. The attacks and threats to the Cawley family began in October 2006, only days after Mr Cawley was stabbed to death, and continued up to two weeks ago. On St Valentine's Day, a man wearing a balaclava ran up to Janette Cawley's sister, reached for a weapon but then ran off as other people gathered. As he ran away, he shouted he would be back.
In July 2009, a pipe bomb exploded at the home of Mrs Cawley's brother, Michael, in Emmet Crescent, Inchicore. Another bomb was placed under the car of her other brother, Laurence, on Emmet Road in March last year. The Army Ordnance Corps made the device safe.
In August 2007, an attempt was made to burn Laurence McKenna's home while he and his family were asleep. The fire was put out before it caught hold.
The threats and attacks started almost immediately after the Dumbrells stabbed Christy Cawley to death. Ten days after the murder, Mr Cawley's brother, Bernard, was told he, too, would be killed if anyone gave evidence against the Dumbrells. Mr Cawley's niece received a phone call a day later threatening that members of the family would be killed.
Mrs Cawley's cousin, Darren O'Meara, was threatened with murder in April 2007. Threats were directed at Laurence McKenna and his wife in Emmet Road a week later.
Bricks were thrown through the windows of Mrs Cawley's sister Sharon's home in June 2007. There was another death threat to Mrs Cawley's niece in December 2007. There were two hoax bomb calls to the home of Michael McKenna in July and August 2009.
When Jeffrey Dumbrell took the stand, he told the court he and his brother had merely turned out that evening in 2006 as "minders" for their brother Tommy. He didn't explain why, in that case, Tommy wasn't there.
There are lessons to be learned from this monstrous story so that we can cling to our faith in the presumption of innocence before the law. We must learn from experience to doubt the possibilities of redemption. We do not necessarily have to go down the road of "three strikes and it's life" as they do in some American states, even for non-capital crimes. But we have to accept that there are sociopaths in the world whose thuggery is anything but mindless: it's carefully, brutally thought out, and viciously prepared.
And when we know "beyond reasonable doubt" that society will always be in danger from such people, it's time for "life" to mean just that, however horrible it is to contemplate.
We owe it to victims like Christy Cawley who paid such a terrible price for his stupid bravado, and to all the other victims left to welter needlessly in their own blood.