After I wrote this post, I spent several hours shoveling from my pile of crushed limestone, and had time to think about the physics involved in that angle of repose. As metaphor, it is certainly limited, in that I fully intend, and actually need to remove that entire pile (and probably sooner, if you ask my neighbors). But as I shoveled, I saw the obvious point not made in my last post, that the angle is disrupted most from the base.
To follow this further with evangelical Christianity, the problem is the erosion from the supposed principles of the base, or the faith's raison d'etre. To put it plain, if Christianity can so easily abandon the poor and the "least of these," then, to quote another truism, "there is no there there." I also see the obvious problems with that assumption, given that this is certainly not the first time that Christianity has aligned itself with evil. Slavery easily comes to mind, and I know that is far from the only example. And I also realize that we have to be fair in acknowledging that Christianity is powered by flawed and human people. People who would deny Galileo's observations, or the humanity of Native Americans, or who would see an obvious inferiority in blacks and women. To that point, this is a continuity, not a conflict with the church's history.
To me, however, this current incarnation represents one of the worst conflicts--not because it wasn't horribly wrong to endorse slavery or native genocide--because this represents a clear and conscious rejection of the faith's own basic and known tenets. Slavery existed because there was no real clear legacy of equality. By contrast, Christians absolutely used to see poverty as one of their primary enemies. And by "used to," I mean in the past 25 years. It isn't as if Christians are going along with the rest of culture in accepting some kind of inequality. They are actually moving backwards here.
Following the logic of the metaphor, when that base is completely eroded, there is absolutely no Christianity left. That might be worth a conversation or two in evangelical circles. But I am not sure that will happen. Sadly.