Episcopal preacher Sarah Dylan Breuer, who blogs over at Sarah Laughed, has suggested this list of core beliefs to remind both factions of our divided communion that our similarities in essential matters may outweigh our differences. The comments below her post offer worthwhile additions, mainly emphasizing human sin and the necessity for grace. Other commenters note with dismay that some liberal churches within ECUSA now reject the very idea of collective agreement on doctrine. Sarah’s list:

Jesus is Lord. Jesus and the God who created the universe are one.
The Old and New Testaments were inspired by God, and are useful for teaching and Christian formation (a la 2 Timothy 3:16-17).
Jesus of Nazareth was an actual historical person who was born of Mary, gathered disciples and taught, healed, and confronted evil powers in ministry the first-century Roman province of Palestine, and was crucified under Pontius Pilate’s authority.
Jesus of Nazareth was and is the Christ of God.
The God of Israel raised Jesus of Nazareth from the dead. I know some Christians struggle with this, but I believe this was a bodily resurrection, and the tomb was empty (and John Dominic Crossan never persuaded me that there was no tomb).
Jesus’ disciples met the risen Jesus — some had visions, some corporeal encounters (though Jesus’ body was different in some ways — e.g., he didn’t seem to need doors to be opened or unlocked to get into a room), but in all cases reported in the New Testament it was Jesus they met.
I think the list of canonical books in the New Testament is a good one. There is no non-canonical gospel that I would have liked to see in the canon, and no book currently in the canon that I’d exclude if I could.
I believe that the kingdom of God was inaugurated in Jesus’ ministry, and that Jesus will come again to realize fully his work among us.
I believe that the God of Israel has chosen Jesus, the Christ, as judge of the nations.
I believe that Jesus is really present in the sacrament of the Eucharist.
I believe that Jesus is really present wherever people gather in his name.

For what it’s worth, I hang my hat on the Nicene Creed and Romans chapters 6-8.

Whatever our list of essentials, we have to decide when it is worth splitting the church over differences in interpretation. Are we all worshipping and loving the same Lord as revealed in Jesus? Then maybe this marriage can be saved. But if some of us define Jesus as “God incarnate who died for our sins” and others define him as “a good role model in a world where we must save ourselves through good works,” then the whole project may become too incoherent for us to pursue it under the same roof. The gay/straight division has become a proxy for so many deeper theological divisions that it does not correlate with at all — perhaps because fallen human beings would rather fight about morality than come together in our need for grace.