I think the big problem with this whole situation is that we, as a country, are too dumb to comprehend what is actually happening. People hear "Trump is working with Russia" and they assume that situation has to be just like the movies: secret meetings, years of planning, code names, etc. Naturally, all of that seems too far-fetched, so they reject the entire premise.
What is happening is much simpler to understand, but just as dangerous. Putin has zeroed in on how to manipulate Trump: flattery with a hint of intimidation, and Trump's natural instinct to push back when faced with criticism and never admit defeat has pushed him further into Russia's arms. The issue with this is that Trump is not smart enough to see through Putin's strategy, and now I genuinely believe that Trump thinks that Putin is acting in America's best interest, when literally every piece of evidence says otherwise. He doesn't think he's doing anything wrong because his brain cannot comprehend that he is being manipulated on this scale, therefore everything must be okay, which results in him doubling down.
People hear the word "collusion" and assume it has to mean some sort of long, drawn out plan, but here it is simply a power-hungry imbecile who is too stupid to realize he is being played. That doesn't make it any less damaging, though.