"The answer is simple and so obvious that it gets totally overlooked" So I am a clueless rube. Let me explain.
I am not a bigot, but I understand how bigotry can drive a person;s political beliefs. So I completely understand why the Republican Base (for most of them) are attracted to Trump. He figured out what the driving force was of the Base and tapped into it. The result of their bigotry is now called White Rural Rage. Everything these folks hate about the federal government can be distilled to bigotry. So I get the 35%-40% who continue will will never stop supporting Trump. Did you see the video from one Miss university???
So the question becomes what motivates the 10-15% who support Trump, to make up the 50% support he gets in polling. Presumably these are independents. If they are irrational thinkers and it simply a beauty contest, I get it. They are my stupid electorate. I suppose some like the authoritarian nature of Trump i.e. he should be king. Again, my stupid electorate. Etc. No objectively rational person would consider Trump a good candidate, even if he were running against a dead ham sandwich. Trump is a narcissist whose only concern is garnering popular adulation at whatever expense it costs the country. Trump is incompetent. This is proven in his business dealings. Trump as a self promoting narcissist uses grifts as a means to elevate his ego at the expense of other people. Trump has an authoritarian streak in him (based on his narcissism)for which he will destroy Democratic institutions in order to idolize himself. etc.
Since I am clearly not very smart, the answer is no, I do not have a clue what is so obvious.
