Leading article: MPs must update our laws on life and death

The US Declaration of Independence defines life, liberty and the pursuit of happiness as among the unalienable rights of every human being. And that affirmation has provided a model for legal rights the world over. There are times, though, when this combination, which sounds so obvious and reasonable, comes sadly unstuck; when life, liberty and the pursuit of happiness can seem to be at best incompatible, and at worst negate each other.

This is the distressing plight of Tony Nicklinson, whose anguished plea for help to end his life was rejected by the High Court last week. Mr Nicklinson has been paralysed from the neck down since a stroke seven years ago and he says that his life is no longer worth living. He finds himself in the ultimate catch-22 situation. He is adamant that he wants to die and his family respects his wishes. But his condition makes it impossible for him to commit suicide except by starving himself. The court, in a ruling he is likely to appeal, rejected his plea on the grounds that it would in effect legalise euthanasia, and that changing the law was a matter for Parliament.

As it happens, the judgment is due today in a case that might be seen almost as the mirror image of Mr Nicklinson's. The family of a man known only as L is trying to prevent doctors from declining to resuscitate him, should his condition worsen. L suffered a heart attack five weeks ago, which doctors say has led to severe brain damage. His family does not dispute this, but their lawyers have argued in the Court of Protection that it is too early to be so categorical and that, with time, his condition could improve.

Judgments in previous cases that appear similar suggest that the family may be disappointed. The testimony of medical experts acting for a hospital or health authority has generally, though not always, been accepted as the last word. That L's case is being considered in court at all, however, illustrates how delicately balanced such decisions can be and the passions they raise on both sides.

Nor is it coincidental that such cases seem to be coming before the courts more often. With people becoming better informed about their medical options, the authority of the Church waning and the capacity of medicine to prolong life continually advancing, it is probably to be expected that the ultimate ruling in the most acute cases will end up in court. It was only last year that Debbie Purdy, who suffers from multiple sclerosis, won a partial victory in a long judicial battle to minimise the risk of her husband being prosecuted if he helped her travel to Dignitas in Switzerland.

What is also clear from the rulings handed down, however, is that judges feel uncomfortable being placed in the position of arbiters, where matters of free will and the boundaries of life and death are concerned. And while they see it as their duty to uphold the law and there are good reasons why that law is as it is – those who find themselves terminally ill or disabled may be vulnerable and susceptible to pressure, while their families, for whatever reason, may not always be motivated by benevolence – those same judges also recognise that the law is at times inadequate, or out of step with evolving public opinion.

This is where Parliament comes in – and it should do so as soon as possible. MPs may be as reluctant as judges to amend the law in a way that gives individuals a greater say in how and when to end their life, not least because of the fierce lobbying they will receive from both sides. But if the law is to change – and we agree with Tony Nicklinson that it should – they cannot expect judges to do the job for them. This is a task for Parliament, and one it must not duck.