There have been events in our evolutionary history where our ancestors took different paths that lead to us. Is it possible that we are at another of these branching points? Isolation of pockets of a population can over time lead to the creation of two different species.
The question we must ask: Are the wingnuts branching off to form their own species?
The wingnuts seem quite different than us in many ways. By and large they look like us, but there are differences. Some of these differences the wingnuts have observed themselves. There are dietary differences, for example, we are told that our population has an inherent inclination to lattes and sushi, as well as an uncanny lack of fear of quiche. Our population uses technology differently, having a natural affinity for Volvos and Twitter.
The wingnut population on the other hand drinks beer and eats meat, which apparently our population does not do. In addition, they have an inborn fear of quiche, which they feel will cause them to become unmanly. Their population has a natural inclination to pickup trucks, which explains why they use them even if they have nothing to haul and nothing to tow.
There also has been observations made by members of our population. Just as we are dependent on nutrients like vitamin C, which our bodies cannot make ourselves, we are dependent on things like facts, which we cannot make for ourselves. Our population seeks out facts, and actually checks them to see if they are genuine facts.
The wingnuts on the other hand, seem to have evolved past the dependence on facts, much like a species might develop the capacity to produce their own vitamin C. They can, all on their own, create any fact they wish, on command, for whatever the situation calls for. This ability to produce your own facts allows the wingnuts to continue without ever having to change their mind, while our population, being dependent on facts that exist are required to change our minds from time to time as the facts dictate.
Furthermore, it appears unlikely that members of our population would consider wingnuts to be desirable mates. The concepts "X is a wingnut" and "I want X to be the <mother/father> of my children" tend to have a negative corelation. Sexual selection would appear to favor a further separation between these two populations.
It should also be noted that natural selection is not the only force at work here. Much as a farmer favors some crops over others, the right-wing media and think tanks have been nurturing this population.
Given grumblings from the wingnuts about secession, there is an open question whether they want to go farther still and secede from our species itself. The taxonomy of this new species is still not clear. Would it be called "homo non sapiens"? "homo wingnutia"? Or perhaps "homo sapiens NOT!!!"
Would secession from our species be sufficient? Given their tendency toward homophobia (which some say explains their tendency to dwell in closets), perhaps remaining in the genus "homo" would be too disconcerting, and they would prefer to leave our genus altogether, creating a new genus "hetero".