What is the theme in The Brethren: Inside the Supreme Court by Bob Woodward and Scott Armstrong?

One of the themes that carries throughout the book is the role of protocol. Protocol here refers to how they do things at the Supreme Court. This doesn't just means who sits in what chairs or walks in what order. The term is used here to describe the unwritten rules that prescribe behavior. For example, the Justices meet in the conference room to vote on cases having to do with petitions for cert or after hearing oral augments. The unwritten rules determine the order in which they talk and vote. This is usually done in terms of seniority in that the most junior member is that last to speak.