The Moon Is A Harsh Mistress was, at least in my opinion, his version of the American War of Independence and Heinlein's greatest novel. AI in 1965 was pretty forward-looking, but when the girls died in the fighting at the ramp it was pretty obvious he was talking about something else entirely. That was his version of patriotism, the real one.
“Moon” is a great book, and was in fact the first Heinlein I ever encountered. If nothing else, it deserves remembrance for popularizing the phrase “there ain’t no such thing as a free lunch.”