Capote is 95 percent those two men, Truman and Hoffman, character and actor, feeling one another out. But in focusing on that particular period in Capote's life, screenwriter Dan Futterman also offers insights into the climate of the age, and the place of women within it. Capote's research assistant was Nell Harper Lee (Katherine Keener), eventual author of To Kill A Mockingbird. The dismissiveness with which Harper is treated and the diminutive way she handles it is perfectly indicative of the period. It's all the more illuminating to play down Lee's eventual fame like that, as director Bennett Miller shoots the film almost completely through the eyes of Capote, whose cult of personality had no room for other gods besides himself.
As a look at American life, in general, during the writing of In Cold Blood, Capote is a strangely illuminating vignette. As a look at the life of Truman Capote himself, though, it's far more opaque -- a disquieting and labyrinthine portrait of a charismatic and ultimately self-deceptive talent. The more time we spend with Truman, the more complex he becomes and the less we ultimately understand him.
As Hoffman's Truman comes to realize the effect his interference has on the life of the murderer Perry Smith, his exploitive tendencies and his strange, magnetic empathy, which had been working together under the banner of his fame-seeking narcissism for so long, begin to separate. Eventually he finds himself unable to treat Smith's torment, frustration, rage and hope with the clinical gaze he'd intended. Of course he still willfully exploits Smith's story, but Truman realizes for the first time what that means about him as a person. Capote says early on, "ever since I was a child people thought they had me pegged ... but they're always wrong."
By then end, it's clear he thought he had himself pegged, that his ego and his journalistic detachment would allow him to weather the ordeal of writing this book about these people. It becomes obvious, though, that the person who was most wrong about Truman was Truman himself. It's in this crumbling that Hoffman's performance becomes more than simply a really good impersonation, and something more like a piece of art.