TEC is a pioneering Anglican church. That has always been its history. First Anglican church to make an episcopal beginning without the helping hands of mother England. First Anglican church to revise the Book of Common Prayer. First Anglican church to consecrate women bishops, openly partnered gay and (soon) lesbian bishops. It will vie with Canada's Anglican church for which authorised blessings of same sex partnerships first (and, even harder question for future historians, for which tacitly approved unauthorised blessings).
One reason for paying attention to what is happening in TEC is because of the strain this pioneering spirit is placing on the Anglican Communion; and, yes, it is how some Anglicans are reacting to that pioneering spirit which is also placing stress on the Communion. Another reason, especially for Anglican churches in Western liberal democracies, is that where TEC goes, we may follow, or should follow. Or, perhaps, should take care, study carefully, and not follow. It is a truism these days that many churches in the West are in decline. So hearing about decline in TEC is not reason in itself to disregard the possibility of following her lead. But I think - on the basis of many readings on the internet - that it is possible that TEC is (a) on a path of faster decline than the rest of us, and even of disintegration; and (b) heading in a direction in which, ultimately, its inclusiveness will prove to be highly exclusionary. If that estimation of where TEC's pioneering spirit is leading it is correct then I urge caution on my own church, a church which has many influential TEC admirers.
Of course, I may be wrong. I may be latching onto Walter Russell Mead's understanding of where TEC is heading because I am predetermined to do so.
Or he may be a prophet whose honour can and should be recognised far from his home country.