It seems, at times, that Americans are a people of the law in the same way that most American Christians are a people of the Book.
In both cases, there are vast industries dedicated to expanding, explaining, twisting & obscuring the core elements (the Constitution on the legal side, the message of Jesus on the Christian side) while making huge profits & deriving vast power from such activities.
The citizens generally don’t know how law is made (bills, court judgments, administrative rules). Christians generally don’t know how their own version of the Bible came to be. Both buy into mythology about the origins of what they give lip service to. (We literally buy it, as books & shows are sold to us with these myths on a daily basis.)
Both citizens & Christians spend most of their time ignoring the rules & standards of behavior laid out.
And we all have our favorite parts that we love to quote (this Amendment or that, this verse or that) without really studying it to see how it was meant by its author or how it fits into the overall scheme of things.
The term “people of the book” was applied to early Christians by various people due to those Christians’ use of the book format for their collections of writing. Others of that time used scrolls. Christians had bound books. Today, the term is mostly used by Muslims to refer to Christians.