I think the obligation(s) have already been decided by the court(s) in the US. I'd be surprised if it is any different anywhere else.
Courts are fallible. The US courts have made plenty of shitty rulings. No, the ethical obligation remains on each person to justify his or her decisions at large. That is the burden of freedom and consciousness.
To be clear, I agree with a lot of the reasoning in Roe v Wade. But it's rather suspect reasoning to call upon an external council (a Court) as some sort of moral arbiter - particularly when US legislatures and courts have made so many shitty decisions, both in the past and more recently.
"What makes you think anyone other than the mother has any locus standi in this matter?"
This goes back to your belief that until a foetus leaves the mother, only the mother has an ethical interest in the foetus's survival. While I mostly agree with that, there are very, very many arguments (both from a religious and a secular perspective) that go against your assertion. And even if we take for granted that the mother's needs are paramount, not every mother is going to make an informed or rational choice. We don't, for example, allow a mother or father to make uninformed decisions about things like access to IVF, or about post-birth care. To draw a fine-line distinction at the moment of birth can only be a pragmatic and not a logical exercise.
Again, your insistence that only the bearer of a baby can have a choice in the matter is dogmatic. Everyone has a dogma; I at least accept that my views come from it. You seem to ascribe some sort of universality to your starting point. For example, I would have thought that the mother needs to consider the needs of the unborn when weighing up the ethical choice, and since the unborn can't speak, society may have to speak for it.
Why stop at the fetus?
Every human cell can potentially act as the starting point for a genetic clone. If not now, maybe in 5 years. Are you pro-killing-clone-seeds if you like to brush your hair every day?
I don't follow what you're saying. Yeah, every cell can reproduce. But if you kill it while it's still a cell then you've only killed a cell. If you kill a foetus you've killed a foetus. If you've killed a baby you've killed a baby. What I am asking you to do is to:
1. Use direct and accurate terminology
2. Consider the opposing viewpoint at its highest before engaging with it
Yes, it is messy. So the mothers burdened with this decision deserve support, not nosy judgement from the likes of you or me.
I could easily say that foetuses subject to their mother's sole whims also deserve support from the state to ensure that there is some form of oversight. After all, no one - mother or not - is infallible.
While I personally am very pro-abortion and believe that mothers should, in most cases, have the absolute say, I can very easily see the argument coming from the other side.
Perhaps before setting down your opinion you should try to do the same. Take the best faith position you can of any opposing view.