The Spirit of the Laws by Montesquieu isn't a work of fiction, so characters don't appear in it the same way they appear in a novel. There are actors, however, in the political science sense of the word, and if that's what you mean by characters, then there's a lot to discuss. We won't recapitulate Montesquieu's arguments here, we'll preview them. If you want to know about them in detail, you should read the excellent study guide available on this website.
Actors are people who have what we call agency. They do stuff. They're active, as their name implies, not passive. We don't have to know who they are individually. We just have to recognize what they do and what the causes and effects of those actions are. Characters in a novel just show up. They may or may not act, but they're part of the story. Here, actors create political systems.
If you read Montesquieu critically, you realize that The Spirit of the Laws is at least as much a social commentary as a work of political philosophy. Read in between the lines of his theories of...
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