The term "dogwhistle" is appropriate here. Trump said and continues to say certain things that white supremacists happily construe as support for them, e.g. Trump's delay in condemning them tells them those condemnations were done only for political purposes.
At the same time, his supporters who aren't white supremacists can now say that Trump has officially condemned the bad guys, so fuck you snowflake. The question of whether Trump does this by design is immaterial because the effect is the same whether he does it on purpose or if it's a byproduct of his incompetence.
Either way, the right now turns around and whatabouts the hell out of Antifa, an organization with little influence, little history, and almost no identity. It would dry up and blow away upon Trump's demise. Yet in Antifa, conservatives really, really, really want to believe they've found the left's equivalent of the KKK. Of course that's utter shit, but look who the POTUS is. Utter shit is the norm now.
As for Trump supporters online, well, the comments sections of a lot of entities are overwhelmed by fake accounts that claim support for the President. On Facebook I notice that the earliest responses to CNN articles are overwhelmingly by Trump supporters. They seem to have notifications sent to them, whereupon they lay siege to the article almost immediately upon its posting. I don't know what they think this accomplishes, but it sure is annoying.
Anyway, as to the specific mental state of the country, it's sick. We can comfort ourselves all day long that only 30-odd percent of the country is Trump-stupid, but 1) that's a fuck of a lot people, and 2) a person suffering from some form of severe mental psychosis 30-odd percent of the time is a serious danger to himself and others, and likely needs to be institutionalized.
Even if the world were to have the great good luck of a Trump heart attack and subsequent death, Fox News and all of its awful pundits, Rush Limbaugh, Infowars, Breitbart, etc. would all remain to continue to fill the non-critical heads of tens of millions of Americans with dog shit 24/7.
We're so fucked.