Former Massachusetts governor Bill Weld may not be the only person to challenge President Trump for the Republican nomination in 2020. But whatever happens, the Republican primaries will reveal the extent to which the GOP is now Trump’s party, and why.

No one who runs against Trump will have any realistic hope of defeating him. Polls consistently show 80 percent or more of Republicans approve of the job he is doing. That figure rises to 93 percent among people who voted for him, according to the most recent Economist-YouGov poll. Trump also beats all of his potential challengers in head-to-head matchups, from margins ranging from 85-15 against Weld to a low of “only” 69-19 against Sen. Mitt Romney (R-Utah). No one who wants a serious future in GOP politics will undertake this kamikaze mission.

Trump has earned this high level of support because he has delivered on the items of supreme importance to almost every Republican faction. University of New Hampshire professor Dante Scala and I examined these groupings in our book “The Four Faces of the Republican Party.”