In the wider realm of the American culture wars, Robert George has an op-ed about marriage, gay marriage, and the law.
He is writing about our society from a secular/legal point of view, but there is a fearful symmetry with respect to the movement within the Episcopal Church. Normative marriage and family values have been deeply eroded in the United States. Traditionally, religious institutions have been critical to supporting the norms and helping families stay together. For the gay community, particular churches have been the means by which they gain a certain "moral" authority to change the definition of marriage, and none has more cultural influence among the elites than the Episcopal Church (even Tom Wolfe remarked about this in "The Right Stuff": John Glen, of course, was Episcopalian.) If the Christian communities, and particularly the elite, intellectual, and historic Episcopal Church in America, give their imprimatur to the redefinition of marriage, then many people who identify themselves as Christian will be swayed.
In any church, there is a substantial population of people who trust that the leadership are doing "what's best" and don't give it much more thought. There are a few who don't know enough to debate or even question the issue, if it ever arises in any discussion. These people may feel uncomfortable about the way things are going, as I did for many years. And there are many who are stalwarts of the church who put their finger to the wind and gauge the likely outcome. In my church, I have noticed that most conservatives have voted with their feet. Many left around the time that I joined or within five years. I hardly knew them, but I remember that it seemed evenly split politically when I joined. My personal experience as an outspoken Conservative has been instructive. I was the only person in the history of the Episcopal universe to have a group of parents demand my dismissal as a middle school Sunday school teacher- nothing salacious, mind you (thanks to some great Christians, they weren't successful.) I think I'm the only person who's been there for 15 years with a college degree who has never been asked to be on the vestry (lay leadership.) I've watched while others get asked to serve again, and still others who had only become Episcopalians and Christians in the last confirmation class be given places on the vestry. Yes, it's very easy to stack a vestry with people who will play ball and be easily manipulated by the clergy and his/her allies.
The Episcopal Church is a great prize for the Gay/Lesbian lobby and they will use it to some effect, even as they cut funding for evangelization (remember that? bringing people to Christ?) They are closing churches as we speak, but that's OK. We have Ubuntu. In the immortal words of Katherine Jefferts-Schori, it may be worth a schism.