Why can’t a Border Collie be a police dog?

Although Border Collies are very intelligent, their temperament does not suit police work. First, they are crafty — so smart they form their own ideas and like to outwit their handler, often ignoring commands. Second, they are timid and somewhat bully-prone, failing police requirements. They are also playful and easily distracted while training or on duty, and lack the strong aggression needed to deter criminals.