Within the next half century, perhaps much sooner, the right to choose to die with dignity will be as widely recognized as the right to free speech or to exercise one's religion.

It will cease to be called euthanasia or mercy killing. It will not be viewed as killing, but as a fundamental human right as expressed in the imaginary constitutional amendment above.

In Europe, euthanasia is already sanctioned by law in Belgium, the Netherlands and Switzerland. In the United States, the state of Oregon has also allowed it.

The decision last week by a French criminal court in Périgeux illustrates how social mores precede changes in the law. The facts of the case are simple: A 65-year-old woman suffering from terminal pancreatic cancer was given potassium chloride by a nurse and died shortly after.

Potassium chloride is a fatal poison. The dose was prescribed by a doctor and administered by a nurse acting on the doctor's orders. Prior to the fatal dose, the patient suffered from fever, trembling, incontinence, nausea, pain and an intestinal blockage causing vomiting of fecal matter.

The nurse was indicted for assassination and the doctor for assisting. The charges were later changed to poisoning. The two accused risked maximum prison sentences of 30 years.

After four days of trial the nurse was acquitted and the doctor was given a one-year suspended sentence. The court also ordered that the conviction not be registered in national government files, which will enable the doctor to continue to practice. It is not clear who initiated the prosecution. Neither the husband nor the son of the deceased woman pressed charges. In fact, they supported and thanked both doctor and nurse. The prosecution argued that the principle of not killing must be upheld, but the jury did not agree.

The decision shows once again that laws are a lagging indicator of social change.

France revised its law in 2005 and now permits what it terms passive euthanasia, which may mean withholding treatment or giving painkillers in such a massive dose that the patient can slide into an eternal sleep. But it forbids active euthanasia such as the use of potassium chloride.

A generation ago, in 1980, a number of people in France formed an Association for the Right to Die with Dignity (ADMD), which now has over 40,000 members. As medical care improves and people live longer, one can expect to see more such associations around the world, and eventually a change in perspective.

At present, the law focuses on the act of the physician or nurse, and not on the rights of the patient. As that focus shifts so that the right of the patient to die with dignity becomes paramount, one can expect to see the law proclaim a fundamental right.

The fear of abuse by doctors, nurses, or family members wishing to do away with an unruly patient or parent will recede.

Every time we step into an automobile we run the risk of being killed or seriously injured. Yet despite the thousands of auto fatalities every year in every country, the risk is accepted because of the benefits of automobile travel.

The legal philosopher Hans Kelsen defined justice as social happiness. But social happiness is an evolving concept and one that varies from one culture to another.

One need only look at how practices in the workplace — holidays, wages, hours per week, maternity leave for mothers and fathers — vary widely from country to country, and yet are regarded as vested rights in each.

Neither the French nor the American Constitution, nor the UN Universal Declaration of Human Rights, nor the European Convention on Human Rights, includes the right to die with dignity. But then many of the human rights we take for granted today — including non-discrimination and free speech — are far more recent than one might imagine.

One can predict with some confidence that as life expectancy is extended, social mores will evolve and the law will follow.

Ronald Sokol, former lecturer in law at the University of Virginia, practices law in Aix-en-Provence, France.

###