One thing is incredibly obvious if you have a political position outside the mainstream taxonomy: no one in basic left-right American politics takes any position on the basis of reasons. I mean no one, even and especially those who are continually congratulating themselves on their rationality and reality-orientation. Nothing could be more obvious. Everyone has a social commitment to a certain set of positions, and then rummages around in the world for evidence to affirm it and ways to discredit or ignore any difficulties and disagreements. Right and left or Dem and Rep or Trump and stop-Trump: these are fantastical as belief systems, just riddled with holes and contradictions. They are demographic identities strongly tied to other demographic features - region, race, gender, income, and so on. The only role of facts is finding confirmation - not of one's positions, but of one's social identity. That's why these little bubbles work so well. I'm telling you that the positions of a Barack Obama, a Frank Bruni, or an Ivy League professor are no less like this than Sarah Palin's. You've got to deal with people's power, or the fact that they're all over your TV or whatever. But pretending that they are giving reasons or making arguments is very silly.
A good example right now is what the left does with Trump: just global maximal hysteria. White supremacist coup! Any fact that backs that up is a good reason, any fact that throws it into question is ignorance or propaganda. This drifts people on both sides to accept anything uncritically from their own side and ignore everything else or attribute it to pure evil. In the course of things, it has to continually increase hyper-partisan tribalism of an incredibly irrational variety. Of course, I take myself literally to have proven this (not linking it all again).
It's great that we're social animals and all, and perhaps agreeing with whatever jive your tribe has fixated on is adaptive. Maybe cooperation in a group is a more important function than finding the truth in evolutionary terms. Here's why I doubt that. The unity of a group is largely achieved by exclusion, ostracization, war. Our solidarity is characteristically a function of our exclusions. We may kill everything down this road. Also, losing touch with reality on this level just cannot be adaptive. Your whole people will be destroyed by its fantastical prepossessions. You'll be denying there's a problem even as it kills you, etc. I think this is our formula for extinction, actually, the sort of adaptation that ends up killing your species, or which has killed most species that ever existed.
People do have bizarre notions about evolution. Some people think they have to push it along; that is, you show some feature is adaptive or whatever, that shows it's good and desirable. They make 'evolve!' into a moral imperative, which is insane. Evolution does not care whether we live or die. Obviously, it often produces very specialized or almost hyperbolic adaptations (say the huge size of some dinosaur species) which work for a bit, or in a specific niche, or until conditions change. When they do, that adaptation extinguishes the species. For example, if human consciousness is in fact an adaptation and not a side-effect of other adaptations, for example (like an 'accidental' result of more memory or calculating ability), it might take us to the stars or it might end us entirely. That we take it as a mark of our transcendence of animal life or something is just more self-congratulation.
Obviously, we could not persist without social cooperation. But just as obviously, the adaptations that make such cooperation possibly might end up being like the gigantic size of the megasaurs: fatal. But whether or not, they leave us presently in a condition where people are apparently, or even passionately, making assertions or claiming to speak truth, but in which that is quite evidently not the point of their activities at all. People are voluntarily making themselves extremely stupid and constructing fantastic pseudo-worlds. It is not going to end well, or it is not ending well.