Here is the answer I offered to a friend of many years when he posited on my Facebook account that Legalized Euthanasia was logical and a good for our society.
Think of the argument from this perspective. Doctor assisted suicide and euthanasia are ontologically an act by which one person deliberately ends the life of another person. Strip away all extraneous elements; the intention, means, end, or morality, and this is what we are talking about. At its essence, the Supreme Court has ordained that the termination of life by another person be made legal all across the country within the next twelve months. Effectively, it is the empowering of the State by the Court with the faculties and rights to terminate a citizen's life for reasons other than high crimes or treason. In establishing this the SCC blew past a prohibition that heretofore was considered essential in a liberal democracy: the taking of an innocent life. Why do I say State? I do so because in 99% of the countries of the developed world have taken to themselves the management and dispensation of medical services. We access these services with a government-issued card. It is a necessary pre-requisite if one is to participate in a state-run health care system. Doctors and hospitals are paid for from the public purse in accordance with government policy. So to try to frame health care services as being somehow something separate from government policy/service is to stand on a difference that, in fact, makes no difference at all!
This scares the hell out of me. I think it should for most of us. We have not allowed this in times past not because we wanted to inflict pain and suffering on the dying. We've maintained it because history has taught that such a power cannot be vouched in the hands of the State since the State has not proven capable of wielding such power safely.