"The Republican Party is now unrecognizable when compared to the Republican Party of Ronald Reagan and George H. W. Bush. By nominating Trump, the Republican Party allowed right-wing extremists to feel more comfortable inside the party. Reagan and Bush, for instance, did not reject climate science and would step across party lines to cooperate with the opposing party when they felt it was in the best interests of the American people."
"The Republican Party has been taken over by members of various far-right fringe movements."

Far-right fringe movements aren't in control of anything; or, who do you see as being representative of this far-right? Trump? Trump is a former Democrat who hasn't really changed his perspectives on anything. He just ran as a nationalist, and that only works within the Republican party. Besides, he'd never be able to win, running as a Democrat. His objective was to win the seat, and he chose the party where he could pull it off. DO you see the Alt-Right as the ones who've hijacked it? They are in their own little world and don't really control anything in the GOP. They have a level of influence, sure, but to suggest they're taking over is kind of a stretch. DO you think of someone like Dinesh D'Souza as far-right? what about Ben Shapiro? These guys represent what is actually growing in favor and influence in the GOP.

Also, you imply that a distinctive of right wing extremism is to "reject climate science". This is very interesting, and I would love to hear you explain this a bit more. I reject a lot of the claims of so called "climate science", because a lot of the claims are bogus. That'd be another topic to write about though.

Still, though, you've provided a heft of content to pour over here.
I really don't think any of this is as complicated as you're making it, though, but I'll need to look at it more.