The Credentialed Court starts by establishing just how different today's Justices are from their predecessors. The book combines two massive empirical studies of every Justice's background from John Jay to Amy Coney Barrett with short, readable bios of past greats to demonstrate that today's Justices arrive on the Court with much narrower experiences than they once did. Today's Justices have spent more time in elite academic settings (both as students and faculty) than any previous Court. Every current Justice but Barrett attended either Harvard or Yale Law School, and four of the Justices were tenured professors at prestigious law schools. They also spent more time as Federal Appellate Court Judges than any previous Court. These two jobs (tenured law professor and appellate judge) share two critical components: both jobs are basically lifetime appointments that involve little or no contact with the public at large. The modern Supreme Court Justices have spent their lives in cloistered and elite settings, the polar opposite of past Justices.

The current Supreme Court is packed with a very specific type of person: type-A overachievers who have triumphed in a long tournament measuring academic and technical legal excellence. This Court desperately lacks individuals who reflect a different type of "merit." The book examines the exceptional and varied lives of past greats from John Marshall to Thurgood Marshall and asks how many, if any, of these giants would be nominated today. The book argues against our current bookish and narrow version of meritocracy. Healthier societies offer multiple different routes to success and onto bodies like our Supreme Court.