I don't think Trump is the last GOP president. I think he is the first Trumpian president. He's remade the GOP in his own image. The last Republican president was George Bush Jr. Trump, on the other hand, is, depending on how you look at it, a Republican in Name Only or the new face of the party.

One would think the GOP would be so discredited when this is over that nothing viable could arise from its smouldering ruins. However, thanks two our effectively two-party system and Duverger's Law, my guess is that something will arise, that it will still call itself Republican, but that it will be something different than either what Bush OR Trump represented. Hopefully in a good way.

Thanks to the moving of the Overton Window, the Democratic party may well be taken over by the Sanders Progressives and the disaffected soft-corrupt, centrist corporate types will move to the Republican side and fight for "old fashioned values" from there!

Stranger things have happened. Look at how the racist South transitioned from the sway of the Dixie Democrats to the modern GOP, and how those who fight for race equality moved from the GOP of Lincoln's day to the modern Democratic Party.