Honestly, I don't believe the USA will. The Episcopal church is shrinking at a rapid rate. All these politicians you've mentioned have one thing in common - they're all kind of old. And none of them are presidential material. Membership in the church has taken a nose dive and it continues to drop rapidly.
Episcopals will continue to be overrepresented in politics, but as their membership continues to drop, there's only so much over-representation can do for you.
In many ways, there is no longer an Episcopal Church. There are two wings barely within the Anglican Communion. The Diocese of Pittsburgh, to which I have numerous ties, basically left the church. It is stunning to think that the church where my parents met, where my father served as an alter boy, where my uncle sang in the choir, is no longer technically an Episcopal Church.
Just because Pittsburgh, San Joaquin, Fort Worth, and Quincy (as well as the ACNA folks) have decided to affiliate with the Southern Cone over the Church becoming more tolerant and allowing same-sex unions and an openly gay bishop doesn't mean that the church is no longer in existence; the vast bulk of dioceses and members are still part of the ECUSA.
And Pittsburgh. Then there are the people who started attending someplace else. The Church, as a whole has become more fragmented.
I've been an Episcopalian all my life and that's really not accurate. There was a brief period of dissent a few years back when a few dioceses left the church, but I would hardly call it fragmented- even if that doesn't fit the narrative you're trying to push.
I think most people know what the Episcopal church is about, and the acceptance of gay and lesbian clergy is fine with most members, and in fact draws in a lot of liberal Christians who might otherwise have trouble finding a church that suits their progressive views.
