The path from The Boys on the Bus to Playbook is not a straight line. The evolution must obviously account for the anarchic environment of the Internet, the perpetual nature of today’s news cycle, and the rise of ideological journalism, all of which [Mike] Allen incorporates into his daily e-mail. The “pack” still exists, in other words, it’s just bigger and more diverse.

But the one-world notion of the “pack” remains unchanged. Whether journalists are gathered on a physical bus or reading a virtual document, it is a shared space. They are encountering the same names and characters and, after a while, acquiring a shared language and sensibility. “If there was a consensus,” Crouse wrote, “it was simply because all the national political reporters lived in Washington, saw the same people, used the same sources, belonged to the same background groups, and swore by the same omens.”