Every adult, left in its normal environment, supplied with its every need, will eventually, naturally and inevitably become a corpse. Does that 'potential eventuality' make an adult a corpse -- for a fertilized egg is claimed to be a 'legal person' based on its potentiality.
Try this mental experiment:
If a fertilized cell splits in two, and the two cells are manually seperated, we now have two 'potentialities', two 'legal persons' by pro-life definition...
Accepting the above, if then, those two cells are nudged back together, logic dictates a death of a legal person.
In cell 'A' nothing has changed, in cell 'B' nothing has changed. Cell 'B' is the same 'over here' as it was 'over there'.
The only thing changed is its environment.
Now, suppose we had squashed cell 'B' instead of nudging it back -- how would that be different than squashing it without moving it?
Given that each cell in this two-celled cluster has individual potential, would we be morally compelled to seperate them (given that we can at that moment)?
Using the 'problems with potential' illustrated above, and how this potential has been demonstrated to depend on environment, I am personally obliged to seek the next significant event when defining 'legal person', one that is sufficient enough to overcome the 'bodily sovereignty' argument of the woman:
1) If a foreign country drafts its citizens into to fight in an internal civil war, would the world community be morally justified in waging war on that country?
2) If a foreign country allowed abortion, would the world community be morally justified in declaring war on that country?
If a fertilized egg is a legal person, then abortion is murder one. If you do not support penalties that equate abortion to murder one, you are not upholding equal protection under law.
Every millimeter you slip from that equal protection is indicative of your lack of self-assurance of the reality in this matter. Unless your concious is at ease with equal punishment for a woman who aborts and a murderer you have lost your claim at absolutism and must admit that the embryo is 'something less'
If you examine the mappings of (1) and (2) onto the abortion question and practice, you must ask yourself this: If we are not willing, ultimately, to wage war against a country allowing the 'genocide' of abortion, then why wage that war on your own fellow citizen, the woman?
In summary, I place 'legal personhood' at the next significant event: The very first flicker of 'atomistic conciousness' -- the first meta-neural activity: nerve activity that is non-inherent (a heart muscle has inherent neural impulses).
This ill-worded moment, I believe would occur at roughly 4-5 weeks. After that, my conciousness is at ease with murder one punishment for abortion.