The radical right and illiberal left are not a natural state of affairs.
Liberal and conservative are actually personality traits, and we actually need each other to keep us centered in the tao and have a functioning civilization. Liberal and conservative are not coherent political philosophies, and our political institutions are maladaptive.
It is not reasonable to believe that political disagreements are the result of moral failings, stupidity, or mental illness on the part of whoever disagrees with us. They may be in a specific individual, but if your worldview demands that you generalize that kind of thinking to say half of the population, you're probably missing something.
What is the purpose of a conservative political party other than obstruction? What outcome can there be besides incremental failure and compromised positions until the status quo becomes something you had no hand in shaping and no interest in conserving? What do conservatives become when they stop being conservative? Donald Trump apparently.
Progressivism is just as bad, for the same reasons, a century or so of beating your collective head against a wall isn't really conducive to the kind of thoughtful, peer-reviewed marketplace of ideas or selection pressures that result in progress.
Fundamentalism and post-modernism are two sides of the same pathology, they feed on each other, they turn people against evidence, truth, the scientific method itself and thereby their own values. That's how you end up with "conservatives" against nature, institutions and culture and "liberals" against civil rights, civil discourse, diversity and equality, and a complete inability to communicate effectively across paradigms.
We'd better stitch our culture together pretty soon, we're living in a critical moment in history and history is moving incredibly fast. Things could get away from us in a way that will make us wonder how we were so caught up in our differences we couldn't avoid it.
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