I worry that even if we had a Walter Cronkite, the balkanization of the media would mean that he/she would just be ignored or even ridiculed by many.  But I can think of two ways two get back on a straighter road.

1)  On the Right, they have to (at really high levels) stop pushing populist candidates and make a commitment to try to win in less dangerous ways.  I don't have confidence that they'll do this but perhaps if they experience an eventual collapse of support.

2) On the Left, they might want to think about not giving people easy excuses to disbelieve or distrust so much of the media and intelligentsia.  That might mean moving more deliberately and, yes, more slowly on issues like bathroom access, transgender sports participation in womens' events, and other similar things.  This might not be a very popular position to put forth on this board (I realize that), but the sheer speed of movement on some of those issues in the Obama years (and even through some of the Trump years) has pushed people in ways they really didn't need to be pushed.  Patience.  

We might look back 50 years after all this and study it as just a bump in the road, but while living it, it seems brutal.  Look back at the history of the "know-nothing" party and see that we've seen situations like this before.  

A steady, capable, and steadfast but not knee-jerk leader can slowly sap the strength of these kinds of populist movements.  And to do that, he/she MUST keep the economy going in a reasonable fashion, which means not immediately heaping on massive new regulations and taxes (some, and perhaps in some targeted areas could be handled).   

That's my recipe.