The National Council of Churches' 2011 Yearbook of American & Canadian Churches reports the longstanding trend of growth in conservative churches (Catholic, Mormon, Assembly of God, Jehovah's Witness) and decline in liberal churches (Presbyterian, Episcopal, Church of Christ). Every pro-life, pro-marriage church saw member increases, whereas, as Bill Donohue quips, "those religions whose teaching on abortion and marriage approximate the views of the New York Times and NPR are in free fall."
I'm sure prodigal liberal churchgoers are swelling the ranks of "spiritual but not religious" self-identifiers and non-attending non-denominationalists. The moral relativism, progressive policies and multicultural sentiments of liberals put them at odds with the theology and culture of religion. It makes more sense for them to discard religion than to search for a mildly inoffensive brand thereof. The lingering human appetite for spirituality in these would-be atheists explains the modern rise in counterfeit religious substitutes. Psychotherapy replaces confession, social networking replaces parochial community and spiritualism replaces faith.
Faith and reason are mutually complimentary and reinforcing. Liberalism within the context of faith is unreasonable, and hence unsustainable. Conservatism is naturally more compatible with faith, and the trends reported today are likely to continue ad infinitum.