[aNYCguy]

Well, they have the burden of proof, beyond a reasonable doubt, to prove a fetus is not a person.

No, they don't, at least not in the way you're thinking, and this is where you've missed the point.

When someone is protected by the constitution (that is, they are a "person" according to the constitution), then they cannot be deprived of life or liberty without due process. This is not the same thing as the question of whether an entity is in fact protected under the constitution.

I don't believe you're intentionally trying to use this red herring, but have just gotten confused.

[MeanWestTexan]

Sure, it’s not the same thing, but there is no reason why the analysis should not work for both parts of the sentence.