The best thing Barack Obama had going for him in 2008 was the near total dearth of a public record. It is not that there was no such record. Obama had been a professional rabble-rouser—which is to say a “community organizer” in the Saul Alinsky mold, who made common cause with revolutionary Leftists. Later, when he decided to seek public office, his coming-out party was held in the living room of two former Weather Underground terrorists. Still, Obama’s pre-presidential political career was meager and distinguished only by his propensity to vote “present” rather than take accountable stands.

With the press bleaching away his radical roots and studiously indifferent to such basic information as his upbringing, education, and résumé (or lack of same), the candidate was elusively depicted as a “pragmatic centrist.” In effect, he was a blank screen and “Hope and...