“My point is wider.
No government, on either state, local, federal or intergalactic level can allow abortion, or any other form of murder, and itself stay legitimate, regardless of how various citizens vote and what the Constitution says, with all respect for the latter.”
Then I am afraid I must disagree, I define the legitimacy of a government upon the consent it has of those it governs.
Not every government has the consent to prohibit killing(including but not limited to abortion). You might find such a government rather odd, but I’m sure to the people living under it by in large it is acceptable.
Any State of theses United states may by its people be either authorized to prohibit killing or permit to any variable extent their values might deem proper.
A country of fools and murderers that agreed to a law that allows murder may have adhered to the due process for arriving at such law, and they may think their legislation is as you call it “acceptable”, but the law is still not legitimate in absolute terms of justice and therefore neither is their government.
Truth in general does not depend on the number of people finding falsehood acceptable. 2+2 is still 4, abortion is still murder, murder is still an unjust act, etc.