James K. Polk steps onto the national stage the way a man steps into a room where the argument has already begun and the hours are numbered. He is not the loudest voice in the party nor the most beloved figure in the country. He does not look like a romance. He looks like a ledger brought to life—compact, exact, already measuring how many days remain between promise and audit. He comes from a plain Tennessee house, trained by the disciplines that make ambition tolerable to neighbors: work, punctuality, a belief that talking should accomplish something that can be seen on a map or counted in a book. His apprenticeships are severe and useful. He learns parliamentary combat under Andrew Jackson’s shadow and then without it, chairing committees until he can steer an entire chamber, rising to the Speakership with the calm of a man who thinks power is  ...