I think it was clear to most that Trump wasn’t your standard Republican, so I don’t think many were expecting someone who would be the standard bearer for the Republican party. But let’s talk brass politics. What is the benefit of opposing Trump for the Republicans? That seems the quickest way to immediately submarine any chances of enacting a conservative agenda. Their best bet is to manage him as best as they can. What has he done? He nominated a conservative justice. He put serious effort in helping pass healthcare reform in the house. He’s signed multiple CRA regulatory roll backs. These are real and substantial achievements.
He’s a thin skinned, egotistical, man child, but he’s president and open to enacting the Republican agenda. Conservatives shouldn’t be abandoning Trump, they should be doing their best to help steer him in their direction. This means vigorous defenses of his actions when they advance the Republican agenda and reasoned critiques when it harms that agenda. The American people didn’t elect a conservative, they elected a lifelong Democrat. It’s up to the Republicans on Congress, holding majorities in both houses, to get the President on board with their agenda.