The US Supreme Court has declined to get involved in a capyright dogfight between Mexican fastfood chain Taco Bell and two Michigan men over a talking Chihuahua dog. The two men, Joseph Shields and Thomas Rinks, claim that advertisisng executives at the California-based tacos giant stole their idea for a cartoon Chihuahua spokesdog (called "psycho Chihuahua") after they pitched it more than a year before the company began using the dog in commericals.