Senator Kelli Ward (R-AZ)
Former Governor Brian Sandoval (R-NV)
Senator Mike Lee (R-UT)
Governor Matt Bevin (R-KY)
After the clobbering of Ted Cruz, the GOP establishment found itself in a rut. Voters were angry not only because Clinton had won convincingly, but also due to the very controversial way in which Cruz was nominated. In their eyes, Trump had been vindicated. The new RNC chair, Matt Borges, sought to go after the primary process, blaming it on Trump's rise. A quick and decisive vote from the committee ruled that the schedule would be abolished, and that it would be replaced with the 'Ohio Plan'.
2018 was a rather good year for the GOP, all things considered. They retook the senate and returned to 2010 levels in the house. However, it wasn't all good for the Republicans, as the midterms spelled the end of Debbie Wasserman Schultz's tenure at the DNC. Nevertheless, the RNC felt that the haunting past of 2016 was behind them.
Compared to the field of 2016, the 2020 republican bench was seen as relatively light. This was due to many candidates taken out through scandal or constrained by upcoming elections.
Senator Kelli Ward, who made national headlines following her victory in 2016, announced her intentions early, running on a suspiciously Trumpesque campaign, focused on immigration. Following her were Rubio (who got smacked in 2018), Amash, Lee, Sandoval, Bevin and numerous others. Amash's campaign flamed out after the first few debates, where he failed to make any impact, while Rubio was knocked out after a double digit loss in New Hampshire. Ward eventually won the nomination with ease, despite the establishment's numerous attempts to roadblock her.
All in all; the GOP establishment can't catch a break.