“I think Trump would be a disaster. I think Cruz would have a very hard time in a lot of states as well,” said Stuart Stevens, Mitt Romney’s chief 2012 strategist. Trump “has no policy. It might be fun for a day to get in a fight with the Pope but this is not a way to win a campaign. You can’t go around calling Mexicans racist.”

Stevens argues that the presidential nominating contest is a “long process” that “has to play out” and that Trump won’t ultimately win the GOP nod, nor can down-ballot Republicans be so easily linked to the controversial candidate.

“It is [an] intellectually lazy and dishonest attempt to say that just because Donald Trump is running that way that all Republicans are this way,” he said.

Unlike some other vulnerable Republicans, Dold is not waiting to distinguish himself from Trump in his suburban Chicago seat, where Democrats are likely to turn out in droves to back their presidential nominee. And it is not an idle concern that moderate Republicans — or independents who might support a Republican in another presidential year — will choose to either stay home or worse, back Hillary Clinton or Bernie Sanders.