If Clinton was elected President in 2016...

[dw93]

I doubt it. Trump would've been painted as a RINO by the base and would've been seen as too extreme by everyone else. 2020 after a Clinton win in 2016 would've either been the GOP's 1992 or they would've nominated someone who, while right wing, was more genteel and less outwardly offensive than Trump. At most Trump would've likely tried, and failed, to play kingmaker but that's it.

[dw93]

I think there's a case to be made for Trump maintaining a grip hold on gullible rural America.

It's possible, but is that alone enough to win the nomination in 2020? After seeing Neocon War cheerleader and his proto Trump running mate go down in flames in 2008, Flip Flopper and his Tea Party darling of a running mate lose a winnable election in 2012, and baggage plagued narcissistic businessman and his theocratic running mate lose an even more winnable election to a flawed opponent in 2016, I think the GOP would go in a more (on the surface) moderate direction for 2020.