Upon further reflection, a possible POD for an earlier women's right to vote would be if Salmon P. Chase either edges out Lincoln for the 1860 Republican nomination, or if he is Lincoln's VP and succeeds him, or if he dies later than he did. OTL Chase was sympathetic to the idea that women were likewise covered by the 14th Amendment
As Chief Justice of the Supreme Court Salmon Chase had appointed John Rock as the first African-American to argue cases before the court, as a pointed statement of equality. Chase also was the lone dissenter in that case mentioned where a woman brought a case to the court on 14th Amendment grounds, but he died shortly after the case and before he was able to offer his dissenting opinion (which probably would have undermined the legal case against women strongly).
An alt-timeline President Chase is likely to force the issue and make a good case at some point. He might well nominate some Radical Republican woman to a position and dare Congress to make an issue of it - that would seem to fit his pattern.
As Chief Justice of the Supreme Court Salmon Chase had appointed John Rock as the first African-American to argue cases before the court, as a pointed statement of equality. Chase also was the lone dissenter in that case mentioned where a woman brought a case to the court on 14th Amendment grounds, but he died shortly after the case and before he was able to offer his dissenting opinion (which probably would have undermined the legal case against women strongly).
An alt-timeline President Chase is likely to force the issue and make a good case at some point. He might well nominate some Radical Republican woman to a position and dare Congress to make an issue of it - that would seem to fit his pattern.