Ben Franklin is the prototype for the celebrity-as-politician. His autobiography is still in print; if he were alive, he’d be on Drudge’s columnists’ list, and command speaking fees that would turn Hillary Clinton green with envy. A popular T-shirt has a quote erroneously attributed to Franklin: ‘Beer is proof that God loves us and wants us to be happy.’ But John Witherspoon? He wasn’t a fan of self-promotion, which was no less prevalent then. Today, in D.C., his statue stands at a tiny triangle where Connecticut Avenue intersects with N Street and 18th Street N.W. It is routinely ignored. At...