Shadow of Power is categorized as “legal fiction”. How much of it is true? Which parts?

“The information on the Constitution’s language is factual and not fiction. To go much beyond this would be to give away basic plot points of the story. Suffice it to say that much of the historical analysis and backdrop for the story is factual and true. So is the political setup with a Supreme Court that is badly divided and resting for its decisional basis in virtually every controversial case on a single swing vote – the one high court justice – the man in the middle. Beyond this, readers will have to decipher fact from fiction, which may not be easy.”