One social factor Douglas Bess almost overlooked in Divided We Stand is the alignment between traditional social elites in the US and the Democrat Party agenda as it developed after Kennedy. Episcopalians have traditionally been regarded as members of the elites -- but the sociopolitical outlook of the elites has increasingly focused on pansexualism, a bias against public expression of Christianity, and a tendency to romanticize the lumpenproletariat, which costs them nothing, since they're protected from it in gated communities and security buildings.
A good example of elitist Episcopalianism is the late Episcopal Bishop of New York Paul Moore Jr, a product of St Paul's School and Yale, civil rights crusader, antiwar activist, and despite fathering nine children, a closeted gay man. The overall problem with this as a pastoral strategy is that it's less and less important to be a Christian of any sort to be a member of the elites. The demand to get into Yale continues unabated, the demand to go church on Sundays not so much. Indeed, the clear direction of the Democrat-aligned elites is to favor public expression of Mohammedanism as a counterweight to any remaining tendency to witness Christianity in public.
Paul Moore Jr, though, is dead, and his Episcopal Church is on life support. It is no longer an effective strategy, if it ever was, to endorse Christianity by saying that all the right people do it.
The Catholic Church has only occasionally been caught up in this confusion. A tendency not to be elitist has been a principle consistent with its founding. Catholicism in the US has been associated with blue-collar communities and immigration. Alfred E Smith, the Democrat nominee for President in 1928, was a Catholic of the older populist style who had much in common with Truman, or perhaps indeed Mr Trump (who of course is not Catholic). Roosevelt, an old-money bow-tie Episcopalian, was an elitist of an entirely different sort.
Bishop Barron, whom I take to be an indicator of mainstream Catholic thinking, has sometimes taken note of these developments in US politics. Here, for instance, he almost goes so far as to say that a Catholic can contemplate being a Republican, though he presents Paul Ryan as perhaps the best example. Not all Republicans would endorse that assessment, and in light of unpredictable developments in 2016, it may be overtaken by events. I hope Bp Barron will revisit the example of Al Smith.
As Douglas Bess pointed out, The Episcopal Church took no notice of the "continuing" movement, which is also now on life support. The ACNA, while somewhat larger, isn't likely to reverse the trend of main-line Protestant decline, and its future beyond the present generation of leadership is uncertain. It's unlikely to be a successful strategy for any denomination to try to emulate Episcopalianism. As a result, it was probably a good move to put a real Catholic bishop in charge of the US-Canadian Ordinariate. This still leaves open the question of precisely what the Ordinariate is trying to accomplish over the long term separate from the strategies of the mainstream Church.