I have heard that before, but never was convinced of it. In the Curzan case, the lower court and appellate court said to pull her tube based on clear and convincing. The MSC and USSC saw it otherwise at the time. Clear and convincing has precedent all the way to the top. The Florida State Consitition is not silent on this matter either.
Right, but all that happened in the Cruzan case was that the case was sent back to the same trial court judge, who was instructed that he needed to determine that evidence was clear and convincing. I don't recall the exact timeline in Terri's case, but I believe her parents did appeal on that basis, and the appellate court handed the case back to Judge Greer, who then decided that clearn and compelling evidence existed.
One fundamental problem with the appeals system is that it's predicated upon the assumption that judges are honest and reasonable. In a way, this makes sense, since an open acknowledgement that judges were not sometimes dishonest or unreasonable would open up a huge can of worms. On the other hand, power corrupts and absolute power corrupts absolutely.