This book was written in 1987. If read at face value, it projects a future in which the American republic decays into civil war and eventual dictatorship in the same way that the Roman republic collapsed and was replaced by the Empire in the first century BC.
The central character (Granville) James Corbin, who narrates most of the book, has a life story extremely similar to that of Gaius Julius Caesar. Note the initials.
To give you an idea how close the parallels are, the book opens with Corbin describing the circumstances of his birth, referring to a legend that he had been born by Caesarian section, and adding that this was a myth. (Just as the legend that the historial Julius Caesar was born by C-section is almost certainly also a myth, along with the associated suggestion that he has given his name to that medical procedure.)
Throughout the book, after a chapter narrated by James Corbin, there will be a short section from one of his friends, associates, or enemies describing the same events but giving a rather different viewpoint. The book allows the reader to choose for yourself whether Corbin is a hero, a liar and villain, or both.
Essentially this book retells the life of Julius Caesar in what, at the time the book was written, was a near future setting. By now the dates referred to in the first half of the book have come and gone, and real history in the intervening period bears no resemblance whatsoever to the story in tbe book. If you want to enjoy the book as a work of near future fiction you can simply put all the dates back twenty years or so, and it works.
Alternatively, you can see this novel as a light-hearted way of imagining the life of Caesar in a context which is about as close as a modern set of circumstances could have come to the historical circumstances of his time.
Not to be taken too seriously, but quite entertaining in places.