As I read the posts on social media and the cultural commentary from all sides, it seems to me there are four primary heresies-- Four Horsemen of the Post-truth Apocalypse, to borrow an image from Revelation-- that are destroying authentic Christianity "from the inside out" during these days:
First is the dual heresy of reducing Christianity completely to political affiliation and political action. This comes in a Right Wing version (The Religious Right; The Moral Majority; The Evangelical voting bloc) as well as a Left Wing version (which trends toward Socialism of some sort, and identifies with the #notmypresident faction, but has not coalesced under a label yet).
Second is the dual heresy of exempting Christianity from politics altogether and retreating into the private sphere of personal fulfillment. This also comes in a Right Wing version (seen in various ways in revivalism, charismatic spirituality, and prosperity gospel movements), as well as Left Wing version (seen in Oprah Winfrey style universalist mysticism and human potential movements).
All four of these heresies subtly, and not so subtly, move the focus away from following the Risen Lord Jesus as we continue his mission to heal and liberate our selves, our communities, and our world. They turn our focus instead on attaining power and influence in the world to the exclusion of rivals, or conversely seeking pleasure and prosperity for ourselves to the exclusion of neighbors.
The challenge of our century in Western Culture, it seems to me, will be to find a way of following the Risen Lord without falling into these heresies that beset us from all sides. We cannot do this on our own. May Jesus pour out his Spirit afresh and inspire our imagination with a fresh vision of how to live the Ancient Faith in this "Brave New World" of Postmodern, Post-truth, Post-democratic Consumerism.