I had completely overlooked the reference in the Anglican Covenant to the Archbishop of Canterbury as "a focus and means of unity," (3.1.4.I) until Tobias Haller pointed it out in a comment on his blog, In a Godward Direction. I agree with Fr. Haller that such a description of the Archbishop is blasphemous.
The focus and means of our unity is God and God alone. It is the Triune God who has created and redeemed us and holds us together in unity. Creatures like the Archbishop may help us to see our unity in Christ, but that unity is a gift, a work of the Spirit.
Here is yet another reason to say, even if the Episcopal Church were to adopt the Covenant, that it is a deeply flawed, at time blasphemous, and at time idolatrous document. It may be the better course to adopt it - with reservations - and to work towards a better articulation of what it means to be part of the Anglican Communion. Or it may be better, as some have suggested, for the Episcopal to say we cannot accept the Covenant as it is but are committed to continuing conversation with others in the Communion about what it means be Anglican in our various multi-cultural and multi-faith contexts.