Donald Trump needs to pick a vice presidential candidate soon. The Republican National Convention in Milwaukee is in mid-July, and Trump’s relationship with Mike Pence, who served as his running mate the last time he ran for office, became strained when Pence refused to help carry out a coup on Trump’s behalf and came somewhat close to getting murdered by a mob as a result. Which is to say, the job is open because the previous employee who held it was nearly killed by the person doing the hiring. Other Republicans have nonetheless been beating down Trump’s door, in some...