ASK any seasoned trial lawyer and they’ll tell you. When you’re on your feet making a new and challenging argument in court, it helps to have a sympathetic client sitting quietly behind you. John Hirst had none of these characteristics.

On June 23 1979, in Normoor Road in Burghfield near Reading, a 28-year-old Hirst sat watching a Judy Garland movie with his landlady, Mrs Bronia Burton. She was known as “Bett”.

Hirst had moved into her home just 11 days before. He was an itinerant labourer with a prison term for crimes of dishonesty behind him. She was a 63-year-old woman who wanted company and a little extra money. She was ill. She was frail. According to Hirst, she was lonely, demanding, and inclined to nag.

That night, Burton asked Hirst to collect some more coal for the fire. Hirst took himself out to the coal shed, returning with a full scuttle and a heavy hand axe. Hirst struck Mrs Burton on the head with the blunt end of the weapon six or seven times. As the barrister who prosecuted him at the subsequent trial said: “He then went to the kitchen to make coffee and drank it, waiting for Mrs Burton to die.”

Mug drained, Hirst walked around six miles to the nearest police station and turned himself in. The police found him calm, lucid and unemotional. Police doctors interviewed a similarly composed and emotionally absent character. The medics were struck by the 28-year-old’s “immaturity” and “self-centredness”, his general lack of “sympathy for others”. In their judgement, the killing of Mrs Burton was a terrible expression of that indifference. A gross personality disorder was identified.

Hirst pleaded guilty to the manslaughter of Bronia Burton in 1980, reduced from murder on grounds of diminished responsibility. Sentenced to serve at least 15 years in prison, Hirst would spend 25 years behind bars before the parole board was finally prepared to release him as no longer a threat to the public. In 2005, this unlikely litigant persuaded the European Court of Human Rights that the blanket ban on prisoners voting in the UK violated the European Convention on Human Rights.

A less sympathetic advocate for prisoner voting, it is impossible to conceive. Hirst gave the tabloids even more fodder when Strasbourg’s judgment in his case was published, with a celebratory YouTube post, showing the axe murderer “toasting victory with cannabis and bubbly”, a flute in one hand, and what appeared to be a spliff in the other.

“I’m now going to celebrate for the 75,000 prisoners who will be getting the vote,” he said. Determined to alienate any remaining waverers, Hirst claimed this figure “includes murderers, rapists and paedophiles. All of them will be getting the vote because it’s their human right to have the vote.”

With this kind of PR, you can understand why folk who only read the headlines concluded the law is an ass and “unelected Euro judges” are out of touch. But Hirst’s legal analysis was dead wrong. Despite the domestic hysteria, what the European Court of Human Rights really said was “the right to vote is not a privilege” and “in the 21st century, the presumption in a democratic State must be in favour of inclusion”. “Universal suffrage,” the judges said, “is the basic principle.” So far, hopefully, so uncontroversial.

But for the European Court, the essential problem with the blanket ban was that its proportionality. The simple rule was if you were under lock and key, you couldn’t cast a vote. But this policy didn’t distinguish between the wee radge spending two weeks in jail for a breach of the peace from long-term prisoners like Hirst whose crimes were of such gravity that they would rightly spend the better part of their adult life in jail, or the fine defaulters from the serious sex offenders. Can it be right to treat prisoners serving a day and a decade in jail in precisely the same way? And what about prisoners on remand, as yet unconvicted of any crime, but detained till their criminal trials have been resolved? Strasbourg thought not.

So the rule isn’t that all prisoners must be given the vote, as Hirst claimed, but that excluding every one of the UK’s 84,000 or so prisoners from the voting roll couldn’t stand. States have a margin of appreciation to interpret the right to vote in their own way within the framework of the ECHR. Different countries take different approaches. Many write voting rights into their constitution. In the UK, by contrast, voting rights are determined by the whim of a Commons majority. In the overwhelming majority of EU states, including Germany, Ireland and Sweden, prisoners aren’t disenfranchised at all. In fact, this policy is most enthusiastically pursued by Americans, Russians and the British government.

SO what should Scotland do? For most of the history of devolution, MSPs had an easy get-out clause which sheltered them from this controversy. The franchise was a reserved matter. In the lead up to the 2014 poll, the Scottish Government body swerved the issue, excluding prisons from the indyref franchise on technical grounds, and voting down amendments to give Scotland’s 8000 or so prisoners a say in their country’s future. It was at once an understandable bit of cynical politicking and a cowardly expedient. Or, as Kenny MacAskill described it once he had safely demitted office, “doing the wrong thing for the right reasons”.

This week, Holyrood has finally grown up and done its duty. A supermajority of MSPs backed the Government, extending the franchise in Scottish Parliament and local elections to all lawfully resident foreign nationals – and critically, to prisoners serving sentences of 12 months or less. Mike Russell told MSPs that “the bill’s provisions on prisoners are driven by the compelling need to meet human rights obligations”. And he’s right. Holyrood really had no option but to do something to address Scotland’s failure to uphold fundamental rights and freedoms.

But MSPs are to be commended for finding the courage to do so. It is a thankless task and it is all too easy to sloganise. You know the line: “When you break the law, why should you have a say about who makes the law?”

Scottish Tory justice spokesman and depute leader – Liam Kerr – made the wildest pitch in Holyrood this week, arguing that “any member who votes for the bill at decision time tonight is voting to prioritise giving prisoners the vote over the human rights to life, to freedom from torture and to freedom of family life for victims and their families”.

Pretend every man and woman in custody is a murderer if you like. It doesn’t change the reality that this is not so. The idea that MSPs have handed the horrible trifecta of murderers, torturers and rapists the vote is a pop-eyed fantasy. Liam Kerr isn’t a stupid or unconscientious man. As he well knows, the reality is much more complicated than the screamer headline he was angling for. The average sentence for those convicted of serious crimes of violence in this country is well in excess of 12 months.

But there’s also no point in pretending nobody who will cast their vote under this new legislation has committed crimes of violence. Thousands of people who have committed serious offences have passed in and out of Scotland’s prisons – and can exercise the opportunity to decide how they’re governed, so long as they’re outside the walls of Barlinnie and Cornton Vale. Some will. Others won’t.

The Scottish Government has framed this reform as a reluctant legal necessity forced on them. But my heart is with the Greens on this one. As Albie Sachs wrote in the South African Constitutional Court in 1999: “The vote of each and every citizen is a badge of dignity and of personhood. Quite literally, it says that everybody counts. In a country of great disparities of wealth and power it declares that whoever we are, whether rich or poor, exalted or disgraced, we all belong to the same democratic nation; that our destinies are intertwined in a single interactive polity.”

Emotionally, I can entirely understate the desire to expunge someone like John Hirst from the body politick, along with the other men and women whose lives become an essay in the pain and sorrow they inflict on other people. But the awkward truth is this – whatever measures we put in place to deny it, whatever bureaucratic tools we use to pretend otherwise, even someone as uncongenial as John Hirst is part of our community, and it is braver and more challenging to admit that fact, rather than pretending we can exile people like him to a political underworld or to banish them forever. We share an earth, share a country, and share a democracy with these people. Even disgraced, as Sachs saw, our fates are bound.

Imposing civic death on them may make us feel better, just like chasing the scapegoat into the desert may relieve our anxiety. But driving them into the shadows won’t make them or their terrible deeds disappear. Universality is a much more challenging idea than we often give it credit for. It links us at once to the good and the decent, and the bad and the rotten; to the best and worst of our humanity. To its credit, this week Holyrood discovered a little courage, and began to recognise that.