Just one excerpt, out of a longer, and, I think, ironclad argument:
I believe it is unquestionably the law of the United States — today, already, without any need to change the law for Terri's benefit — that due process mandates that no person may be deprived of life by state action unless every factual predicate legally necessary to validate the state action has been proved beyond a reasonable doubt.
[T]he Florida court, which claims (however dubiously) to have made its conclusions using a lesser "clear and convincing evidence" standard, cannot and presumably would not contend that the reasonable doubt standard was used in the state proceedings. Where a taking of life by state action is at issue, the Constitution minimally requires proof beyond a reasonable doubt. Period.
A state court has issued an order that has no other purpose and effect than to kill Terri Schiavo. Without that order, she would be living unthreatened and being sustained today. Because of it, she is being detained, those who would help her are being kept at bay by the police, and she is being slowly killed. Functionally, this situation is no different from the entry of a judgment in a capital case ordering an execution.
The Fifth and Fourteenth Amendments do not distinguish between the lives of capital murderers and the lives of other persons. They don't mention "criminal" and "civil" distinctions. In this context, they command simply that no person shall be deprived of "life...without due process of law." There is no reason in the text of the Constitution to believe that "due process of law" should have a different meaning depending on whether the life to be taken by state action is that of a convicted criminal or that of some other person.
Complementing that textual consideration are the equities involved. Given the absence of any apparent reason for having one set of due process requirements for murderers and another set for everyone else, if society nevertheless decides to have different requirements, why in the world would we think the murderers should get the better process? Such a notion is ridiculous on its face.
It is also unrealistic. Where the Constitution talks about the taking of life by due process of law, it is obviously talking about criminal defendants. At the time of the founding, in the domestic context, the federal and state governments did not kill Americans other than criminal defendants — killing other citizens is a modern development. The people who raise "substantive due process" as if it were a worthy objection have it backwards. It is not we who seek a dramatic change. It is they who push a radical notion: that even though the constitution describes only one "due process of law" for takings of life, and even though the Supreme Court has imposed minimal standards for that due process on the states for eons, somehow, in the last decade or so, there has supposedly grown up, without our notice, a second, laxer due process to be applied to innocent people who haven't killed anyone. Nonsense.