I keep reading speculation about why "moderate" Republicans have all fallen into line behind Trump.
Yeah. About that.
They didn't have to fall into line. They were already in line. Just look at the inexplicably-described "moderate" Republicans who voted to take healthcare away from their voters, who voted to reduce the tax burden on the ultra-rich at the expense of the middle class, and who lined up to put Brett Kavanaugh on SCOTUS. There are no "moderate" Republicans, and the ones who claim to be that are lying.
Trump says and does and believes pretty much everything that Republicans stand for: kleptocracy, racism, misogyny, destruction of protections for workers, the environment, and vulnerable people, transferring wealth and opportunity from the middle class to the ultra rich, and to hell with poor people.
This is the sort of thing that has driven and defined the Republicans since Nixon, if not earlier. The key difference in the Trump era is how they talk about it and how nakedly they subvert the will of the voters and the majority of Americans in pursuit of those goals. Trump has proved (to my horror) that openly racist, openly misogynist, proudly pro-corporate politicians will pay no electoral price for their behavior.
Hopefully, we voters send a loud and clear and unambiguous message in two weeks that there are electoral consequences for how ugly and hateful and dishonest Republicans are, because it sure looks like the Revanchist minority of Americans who are embracing fascism are on the verge of taking over America and remaking it in their reprehensible image.