When I first saw A History of Violence I didn't like it. My initial impression was that it was a lame parable about America along the lines of "If a man with a violent past can be accepted by his loving family at the end of this film then America can still be a proud nation in spite of the terrible things it has done." But this k-punk blog made me re-think it a bit. (You have to scroll down the page, but the images from A History of Violence make the blog about it easy to spot).
The K-Punk thing is a little too much in the vein of Slavoj Zizek, who reduces movies to mere examples for his Lacanian theory, but it makes some good points, the main one being, I think, that everything in the film has the quality of a movie set, so that the whole thing looks artificial from start to finish. This gives it an uncanny quality exacerbated by the fact that when we switch from small town America to gangster-land we see one seamless world, but feel like we shouldn't.
Compare the effect to one used by David Lynch in Lost Highway. In that world we cross over from reality into fantasy but don't yet realize it. In the film Pullman kills his wife because he is ashamed he cannot satisfy her in bed. In jail he imagines that he is someone else, someone who has what he lacks; he imagines he is a virile young man and then is released because, in Lynch-logic, if he is someone else then he didn't kill her. But the fantasy cannot last and reality intrudes until the fantasy breaks down and he becomes Pullman again. Lynch obscures where reality begins and ends but you can still find the divide, once you get how Lynch thinks.
A History of Violence, on the other hand is ALL MOVIE, ALL FANTASY but TWO INCONGRUENT ONES. The Norman Rockwell world and the Gangsterland world are both important parts of the American psyche, but they don't go together. Freud writes that in the unconscious, there is no sence of logical contradiction, there is no organization on that level. A History of Violence gives us a genre film -- two genre films -- on this darker psychic register.