That’s not to deny that an anti-Trump candidate would have to outline positions on policy issues. That imperative raises another problem: Conservative opponents of Trump are more unified in detesting his character than they are on issues. It appears that most of the Republicans who are disaffected in the Trump era are socially moderate — but not all of them are.

I suspect that the protest candidate with the broadest possible support would be socially conservative. We know that Republicans, and people who used to consider themselves Republicans before Trump, are generally willing to vote for candidates who oppose abortion and gun control even if they themselves do not. They voted for George W. Bush and Mitt Romney, after all. Right-leaning voters on the other side of those issues are much less inclined to overlook them when casting their votes. To put it another way: I’m pretty critical of Trump, but if he and Weld were the only candidates on the primary ballot, I’d probably write in a third name.

The criteria for a promising protest candidate are thus not especially stringent. He or she needs to be a conservative, without a large asterisk, with a record of sanity and decency. Surely in this great and large nation, anti-Trump Republicans can find someone who meets them.