“Of all the arguments against voluntary euthanasia, the most influential is the ‘slippery slope’: once we allow doctors to kill patients, we will not be able to limit the killing to those who want to die. There is no evidence for this claim.”  [Italics added.] So wrote one of the world’s leading defenders of euthanasia, Australian philosopher Peter Singer, in 2009.

Some more recent reports agree. A group in the UK which called itself the Commission on Assisted Dying declared in 2010 that there was no evidence of a slippery slope. Earlier this year the Supreme Court of Canada explicitly rejected the idea of a slippery slope when it legalised assisted suicide.

Among opponents of assisted suicide and euthanasia, the words “slippery slope” are ridiculed as a logical fallacy. Why should one bad move necessarily lead to another? The satirical newspaper The Onion once lampooned it by imagining a Fox News TV quiz show called Slippery Slope in which “Contestants try to stay fair and balanced as they negotiate a treacherous obstacle course in which one wrong move leads to gay marriage and two inserts ‘under Allah’ into the Pledge of Allegiance.” It’s easy to poke fun at hyperventilating scaremongers.

So it was surprising to find America’s most quoted bioethicist, Art Caplan, warning that euthanasia in Belgium and the Netherlands is on a slippery slope to abuse of vulnerable groups. In a comment in JAMA Internal Medicine on reports from the Netherlands and Belgium, he and co-author Barron H. Lerner, another distinguished bioethicist, ring alarm bells.

Although neither article mentions the term slippery slope, both studies report worrisome findings that seem to validate concerns about where these practices might lead.

Caplan was a strong supporter of a 2012 referendum in Massachusetts to legalise assisted suicide, and has been consistently “progressive” in his bioethics. However, he is deeply troubled by the data from Europe. From the Netherlands came a report from a specialist euthanasia clinic. The staff of the Levenseindekliniek (end-of-life clinic) are clearly more committed to euthanasia than the general run of Dutch doctors. Their mission is to give lethal injections to eligible patients whose own doctors have already refused. It has a growing fleet of mobile vans (about 40 at the moment) which buzz around the countryside assessing patients’ requests for euthanasia. Despite its interest in promoting euthanasia, the clinic still turned away nearly half of all requests in its first year of operation, 2012, mostly because these patients only had psychological suffering or were tired of living. So the report – which was funded by the clinic — paints a picture of moderation and sound judgement on the part of euthanasia doctors. Caplan and Lerner were not impressed by this cheery interpretation of the statistics. They wrote:

However, other findings are very worrisome. Most notably, 6.8% of those who successfully obtained euthanasia or physician-assisted suicide were categorized as tired of living. A total of 3.7% reported only psychological suffering. Although it is possible that such people were suffering unbearably and not apt to improve, the term tired of living is vague and thus disturbing. Similarly, 49.1% of those whose requests were granted characterized part of their suffering as loneliness. Loneliness, even if accompanied by other symptoms, hardly seems a condition best addressed by offering death. Finally, that 53.7% of approved requests are among those 80 years and older raises red flags. Is old age itself being conflated with suffering? Is it possible that there is a not-so-subtle ageism here among the physicians approving such requests?

About 1 in 30 people in the Netherlands (3.3%) now choose to die through euthanasia. The rate has roughly tripled since 2002, when euthanasia was legalised. The other report came from Flanders, the Dutch-speaking region of Belgium, where euthanasia also became legal in 2002. Between 2007 and 2013, the prevalence of euthanasia there has risen from 1.9% to 4.6% of all deaths – nearly 1 in every 20 deaths. The Flemish authors attempt to explain this enormous change in social mores. First, they argue that “values of autonomy and self-determination” have become more important for the Flemish. And public approval of euthanasia continues to rise, perhaps with the help of very positive reporting in the media. The second reason is that doctors are more willing to perform euthanasia because they are confident that they will not be prosecuted. Euthanasia is even treated as a normal feature of palliative care continuum. Caplan and Lerner are alarmed by this new data. “As the number of overall deaths like this becomes more frequent than 1 in 20, say, I think red flags really need to be raised,” Dr Lerner told Reuters. “Most of us were trained to never condone speeding death at all,” he added. “To the degree that some physicians are comfortable doing so, they will be in cases in which someone has an intractable physical suffering that will only persist or get worse; it is quite a leap for most of us to also see psychological suffering as a valid reason for speeding death.” In their commentary in the medical journal, Caplan and Lerner speculate on why euthanasia and assisted suicide has become so popular in the Netherlands and Belgium.

… the increasing rates of euthanasia may … represent a type of reflexive, carte blanche acquiescence among physicians to the concept of patient self-determination. Or worse, is it simply easier for physicians to accede to these sad and ailing patients’ wishes than to re-embark on new efforts to relieve or cope with their suffering? As one Dutch ethics professor has said, ‘The risk now is that people no longer search for a way to endure their suffering.’ In other words, are the Netherlands and Belgium turning to physicians to solve with euthanasia what are essentially psychosocial issues? …

And they feel that there is a lesson for the United States in these trends:

Although the euthanasia practices in the Netherlands and Belgium are unlikely to gain a foothold in the United States, a rapidly aging population demanding this type of service should give us pause. Physicians must primarily remain healers. There are numerous groups that are potentially vulnerable to abuses waiting at the end of the slippery slope — the elderly, the disabled, the poor, minorities and people with psychiatric impairments. When a society does poorly in the alleviation of suffering, it should be careful not to slide into trouble. Instead, it should fix its real problems.

As recently as last week at a public debate in Sydney, Peter Singer denied that there was any evidence of a slippery slope for euthanasia. It is true that the number of people who request assisted suicide in Oregon, the American state where it has been legal since 1997, is not shooting up. But a steady increase in the Netherlands and Belgium is undeniable.

“The slippery slope is not always a persuasive argument. However, these data and the other recent reports require that it be taken very seriously,” Caplan and Lerner state. “Part of the problem with the slippery slope is you never know when you are on it. Is the use of euthanasia or physician-assisted suicide appropriate for 1 of 20 to 25 dying patients? What if the next round of data indicates that the number has increased to 1 of 10 or 15 patients?”

Let no one ridicule euthanasia’s slippery slope again.

Michael Cook is editor of MercatorNet. 

This article originally appeared at Mercatornet.com on August 17, 2015, and is reprinted with permission.