To be sure, by authorizing doctors to administer lethal drugs, in terminal and non-terminal cases, the Benelux countries go far beyond laws in Oregon and four other states, which permit physicians to prescribe, not administer, a fatal dose — and only in cases of terminal physical illness.

Those limitations, and their effectiveness since Oregon adopted its law in 1997, help explain why 24 states, and the District, are considering assisted-suicide legislation, which 68 percent of the public supports in some form, according to a Gallup poll.

What’s noteworthy about euthanasia in Europe, though, has been its tendency to expand, once the taboo against physician-aided death was breached in favor of more malleable concepts such as “patient autonomy.”

“What is presented at first as a right is going to become a kind of obligation,” Belgian law professor Étienne Montero has warned.