The gaon also didn’t change the established minhagim of Lita for the most part, even though he was on the level of the rishonim – I’m not talking about minhag oilam, I’m talking about accepting the psak regarding a new issue that there’s no established practice. No community historically engaged in infanticide.
I was saying both a rational and a halachik argument; goyim are supposed to keep mitzvos that are largely understandable through honest reasoning. You’re right that i meant chazakah dehashta btw….wrote the wrong one. Also, legally I’m no expert, but it doesn’t matter what American law in itself would have to say if we are compelled to advocate the halachikally ordained position, even if it would mean making otherwise weak legal arguments on behalf of that cause. As it happens to be, it seems to me that roe v wade was a very politically motivated issue, with no legal precedent.