When is a "church" not a church?

I think we can say that The Episcopal "Church" (TEC, American anglicans) - or rather, denomination, as a denomination - is no longer a church. There may be churches among them, and Christians in those churches, but it seems to me that when a denomination deliberately, repeatedly and publicly declared its intention to blesses gross sin, disregarding the Word of God and the gospel it is no longer a church.

Rt Revd Tom Wright argues in the Times Online that the TEC has deliberately formalised schism, torn the Communion and walked apart. To my mind they can no longer be seen as authentically Anglican. Wright talks a lot of sense in that article, though I think he is wrong about the Fellowship of Confessing Anglicans. Even if Anglicanism is already a confessional fellowship, it is no bad thing in such circumstances to have another confessing fellowship that fellowships more closely and confesses more loudly and soundly on the matters in dispute.