"Straw Dogs" is perhaps the ultimate distillation of Peckinpah's views on violence. Peckinpah was an ardent fan of Robert Ardrey, the playwright-anthropologist who hypothesized that humans are inured to violence by instinctual urges rather than social pressure or upbringing. This is a very hard view to argue with, for in spite of hypocritical denunciation of violence in the media, the raging street violence, crime, warfare, and violent action movies, TV shows and video games, indicates that the human race thrives on and revels in killing - no matter how much we may like to think otherwise.
"Straw Dogs" endorses Ardrey's world-view: the people of our out-of-the-way hamlet are easily driven to violence, their sins mostly overlooked by the hypocritically pious town leaders. Even a pacifist like David Sumner is not immune to the allure of murder; his claims of standing up principle (defending Niles, the murderous village idiot, from a mob) are dubious at best. The film has been read as a revenge fantasy a la Death Wish, which is ridiculous; Amy doesn't even tell David about the rape. Rather, it's a cumulative revenge; a man stuck in a small town with no friends, fed up with violence in his own culture, his taunting and torment here, his unhappy marriage to his wife, and his own weakness, allows his long-repressed rage to explode. In the end, even David Sumner is capable of horrific violence; not only that, he enjoys it. And the sheer visceral thrill of watching vile bad guys get handed their just deserts implicates us in the violence as well; none of us are innocent, and all of us are guilty.
Peckinpah's direction is effective, presenting violence in all its glory and horror; he succeeds at showing an externally beautiful but inwardly hideous small town. The cast is good, if unspectacular: Dustin Hoffman embodies David Sumner as impotent professor and makes his transition frighteningly believable. Susan George is quite good as Amy, the confused, repressed young girl who married a guy who isn't right for her. The supporting cast is adequate, with T.P. McKenna and Del Henney giving the strongest performances as the well-meaning but ineffectual Sheriff and the most sympathetic of David and Amy's tormentors.
Straw Dogs is a powerful, disturbing mediation on violence, with a power and force that few films a possess. It is a true masterpiece.