sarai...
As you say, it is a very complicated question and to answer your questions would take a book, not a post, and would depend entirely on what laws were enacted. Suffice it to say that most abortions were both illegal and regulated for most of the history of our nation, more so in some areas than others so regulating abortion is not impossible.
Before Roe v. Wade. the laws regulating abortions were left up to the state and local governments as is constitutionally correct, in my opinion. Incidentally, if Roe v. Wade were to be overturned, it would not automatically make abortion illegal, it would just return control to state and local governments where it should be.
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"How do we legislate and enforce a ban on abortion - without grossly breaching women's rights - human rights??"
I do not believe that any such "right" to abortion exists in Constitutional Law, which is one of the fundamental legal errors in Roe v. Wade. Regardless of one's view on abortion, Roe v. Wade was a terrible legal decision, creating a non-existent "right" out of thin air.
mlsoft