I saw this movie again recently, and I have to say that upon reconsideration I think this film is a bit underrated. There are a few deeper sociological issues being explored here that I perceive but are quite subtle in their appearance in the film.
It is a study about the law to some degree, and it has some critical things to say about the ability for one who knows the law and its loopholes and thus exploits others with tools that were originally intended to preserve civil society. Keaton plays a psycho, but one who is highly educated and quite adept at his craft of fraud and deceit.
Further, Modine's character is irrational, befuddled, and ultimately marginalized. I wonder if the director took some liberties with him (as this is a true story, I don't know everything about the real person he portrays) to bring out a few of his close-minded tendencies that may have contributed to the awful situation in which he finds himself. Obviously, there is the closet racism which keeps him from renting to a black man (this is thrown in the viewer's face later and is quite obvious), but there is also the way he perceives a man's role as the solver of problems and his wife as nothing more than a spectator.
That she ends up being the one to calmly and coolly affect a search for and investigate Keaton's character, assaults the traditional notions of a man's role as a protector. Her temperament is ultimately more appropriate for the solution to the problem, and I think it is no accident that the director portrays it in this way.
