women - What's the deal with female Rabbis?

1) Is there a concrete halachic (Biblical?Rabbinic?) basis for women not being permitted to become Rabbis?

2) After 2000+ years, what changed so the JTS's Commission in 1979 decided that they can?
A sub-question: are they recognized by the State of Israel, or only in America?

I was searching for a while, figuring this was already on here somewhere. the questions about maharat were close but not what I was looking for.