They did recognize it through the mother after the nation recognition of women’s rights, in general.
I agree with you that the courts would recognize bloodline citizenship if it ever had the case brought before it. Should they intervene on their own without a case brought before them? I don’t know if they can do that. The Constitution as I read it says they have jurisdiction over cases arising under the constitution, under the law, and under treaties.
It seems that a case would have to come to them; that they can’t come up with a case on their own.
To have standing in such a case would require a candidate denied access to a presidential election due to bloodline citizenship, and that probably won’t happen.
I don’t read where the legislative or executive could ask them to rule on a question, and I don’t think they’d ask that anyway, since they would be inclined to preserve their own powers.
I suppose a State could bring a case against either a candidate or a fuzzy law, and they could choose to rule on it.
SCOTUS does not issue unsolicited opinions. There are three ways in which a case can be heard by SCOTUS.
First is original jurisdiction, which means that the case goes directly to SCOTUS because lower federal courts do not have jurisdiction to hear the case. For example, when one State sues another State. Such cases are rare - maybe one or two in a SCOTUS term.
Second is an appeal of a U.S. Circuit Court decision in which SCOTUS grants a petition for a writ of certiorari. 9th Circuit Court decisions are reversed more than any other Circuit.
Third is an appeal of a State Supreme Court decision. Unless there is a constitutional question involved, SCOTUS will usually not hear cases on state laws.
Once SCOTUS decides to hear a case, the Legislative and Executive branches can file an amicus curiae brief arguing how SCOTUS should rule and why.
So, yes, an entity with standing under the FRCP would have to file suit before SCOTUS could decide whether or not jus sanguinis citizenship of those born abroad qualifies as natural-born under the meaning of the Constitution.
As they did for Senator John McCain, Congress can pass a non-binding resolution stating that, in their collective opinion, a candidate is eligible. IMHO, they were telegraphing their intentions to the States to avert eligibility challenges.