We'll see.  2018 represents 18 more months of this Trump circus.  People may get very tired of it and vote very differently than it looks now.  The absolute worst thing the Dems could do in 2020 is a run a centrist candidate.  Putting the Blue Dog Clinton in the White House forced the GOP to go waay to far to the right to separate themselves from the Dems.  It is the GOP that will need to re evaluate if they want to stay a white party for whites because in less than a couple of decades the 'fringes' will be the majority.