The dynamic is reminiscent of a joke President Reagan used to tell about a guy who seeks help from a psychiatrist because his brother thinks he’s a chicken. How long has this been going on, he’s asked. Fifteen years. Why didn’t you seek help sooner? Because we needed the eggs, he replies.

That sums up the dilemma Republicans face. They need the eggs; they don’t want to offend Trump’s supporters.

Trump has shone a harsh light on the rest of the Republican field, exposing the vapidity and mediocrity of the candidates, who have been touted as this sterling field of current and former governors and senators. None has shown good political chops; they don’t know how to make themselves and their ideas stand out, to the extent they have any beyond the usual sound bites.

“One of the problems is they’re all scared to death he’ll take his marbles and go home,” says Bill Galston, a senior fellow at the Brookings Institution and former domestic policy advisor in the Clinton White House. “An independent Trump candidacy would destroy the Republican Party’s prospects, and they know it. They have no idea where his limits are—if any exist.”