What will they do if that 6-3 court overturns Roe v Wade and bans abortion across the entire country?
Roe v Wade doesn’t make abortion legal and its absence wouldn’t make it illegal. The case makes abortion a constitutional right based upon a rather weird reading of the right to privacy.
You’ll note that here in the UK we do not have a constitutional right to abortion. We do have abortion. The French constitution does not announce a right to abortion – they have it too. And so on.
Abortion was legal in some parts of the US before Roe v Wade and becoming so in more of them.
If Roe v Wade were overturned – unlikely but it should happen because it was a shockingly bad piece of law even if excellent politics and possibly, dependent upon views, civil rights – then the legality or not of abortion would become a matter of democratic (no, not Democratic) politics in each state. Which is almost certainly where it should be too.
The legislatures – the mini-parliaments of each state – have the power to choose
Quite so. And why shouldn’t this be a matter of democracy?