In the American imagination, the founding era shimmers as the golden age of political discourse, a time when philosopher-kings strode the public stage, dispensing wisdom with gentle civility. We prefer to believe that these courtly figures, with their powdered hair and buckled shoes, showed impeccable manners in their political dealings. The appeal of this image seems obvious at a time when many Americans lament the partisan venom and character assassination that have permeated the political process.

Unfortunately, this anodyne...