This is from the Church Times (1998) by way of John Mark Ministries and t1:9. The whole thing is well worth the read. It has only become more pertinent in the ensuing seven or so years.
Of course the parameters of ethical understanding shift: but the shifts in Christian ethics on, for example, slavery, usury and contraception, have had to argue long and hard to establish that they are in some way drawing out an entailment of what is there, or honouring some fundamental principle in what is there. In other words, these changes in convention have had to show a responsibility to certain principles that continue to identify this kind of talk as still recognisably Christian talk.
This, by the way, is what I take to be more or less entirely absent from ECUSA's efforts to justify its actions: an engagement with the Tradition. If someone would engage compellingly with the Tradition, who knows? A Brave New World of Christian possibility might open up. That's what has tended to happen, through the centuries, with new theological paradigms which the Church has received.