Once assisted suicide is legalized, it becomes impossible to limit the justifications for its use.

Bloc Quebecois MP Francine Lalonde's private member's bill to legalize euthanasia and assisted suicide is back in Parliament.

For millennia, euthanasia (a word I use to include assisted suicide) has been considered morally and legally unjustifiable. People who oppose euthanasia still believe it's inherently wrong – it can't be morally justified and even compassionate motives don't make it ethically acceptable.

But what are the attitudes of pro-euthanasia advocates regarding whether its use needs to be justified, were it to be legalized? And, if justifications are required, what are they?

People who would accept euthanasia, but only in some circumstances, usually limit its access to people who are terminally ill, in serious unrelievable pain and suffering, and require that euthanasia be used as a last resort. These limitations show these people believe each case of euthanasia needs moral justification to be ethically acceptable.

But although the need for euthanasia to relieve pain and suffering is the justification given, and the one the public accepts in supporting its legalization, research shows that dying people request euthanasia far more frequently because of fear of social isolation and of being a burden on others, than pain. So, should avoiding loneliness or being a burden count as a sufficient justification?

Recently, some pro-euthanasia advocates have gone further, arguing that respect for people's rights to autonomy and self-determination means competent adults have a right to die at a time of their choosing, and the state has no right to prevent them from doing so. In other words, if euthanasia were legalized, the state has no right to require a justification for its use by competent, freely consenting adults.

For example, they believe an elderly couple, where the husband is seriously ill and the wife healthy, should be allowed to carry out their suicide pact. As Ruth von Fuchs, head of the Right to Die Society of Canada, stated, “Life is not an obligation.” But although Ms. von Fuchs thought the wife should have an unfettered right to assisted suicide, she argued that it would allow her to avoid the suffering, grief, and loneliness associated with losing her husband – that is, she articulated a justification.

We can see this same trend toward not requiring a justification – or, at least, nothing more than that's what a competent person over a certain age wants to do – in the Netherlands. Last month, a group of older Dutch academics and politicians launched a petition in support of assisted suicide for the over-70s who “consider their lives complete” and want to die. They quickly attracted more than 100,000 signatures, far more than needed to get the issue debated in parliament under citizens' initiative legislation.

And what about avoiding health-care costs as a justification? Although this question has largely been dodged – one could say “religiously” – by pro-euthanasia advocates, euthanasia could be used as a cost-saving measure, and is likely to be if legalized.

Half of the lifetime health-care costs of the average person are incurred in the last six months of the person's life. Euthanasia would be a way to implement a “reasonably well or dead” approach – sometimes referred to as “squaring the curve” of health decline at the end of life, so the person drops precipitously from being reasonably well to dead – which would avoid those costs.

The medical authority of the U.S. state of Oregon – where physician-assisted suicide is legal – seems to have adopted this approach. Shortly before he died this month, Montreal journalist Hugh Anderson wrote in The Gazette that Oregon “has acknowledged that when it turns down an application to cover the cost of an expensive new drug, it sends out simultaneously a reminder that the state's assisted suicide program is available at an affordable cost.” As Mr. Anderson noted, “What a great way to put a crimp in medical costs. Have the patients kill themselves when the cost of keeping us alive gets too high.”

The Netherlands' 30-year experience with euthanasia shows clearly the rapid expansion, in practice, of what is seen as an acceptable justification for euthanasia.

Initially, euthanasia was limited to terminally ill, competent adults, with unrelievable pain and suffering, who repeatedly asked for euthanasia and gave their informed consent to it. Now, none of those requirements necessarily applies, in some cases not even in theory and, in others, not in practice.

For instance, parents of severely disabled babies can request euthanasia for them, 12- to 16-year-olds can obtain euthanasia with parental consent, and those over 16 can give their own consent. More than 500 deaths a year, where the adult was incompetent or consent not obtained, result from euthanasia. And late middle-aged men (a group at increased risk for suicide) may be using it as a substitute for suicide.

Indeed, one of the people responsible for shepherding through the legislation legalizing euthanasia in the Netherlands recently admitted publicly that doing so had been a serious mistake, because, he said, once legalized, euthanasia cannot be controlled. In other words, justifications for it expand greatly, even to the extent that simply a personal preference “to be dead” will suffice.

Legalizing euthanasia causes death and dying to lose the moral context within which they must be viewed. Maintaining that moral context is crucial in light of an aging population and scarce and increasingly expensive health-care resources, which will present us with increasingly difficult ethical decisions.