The amazing thing about Cersei though is that she actually does have a strict moral code that she adheres to. It's ruthlessly brutal, yes, and it doesn't fit in with any sort of realistic moral code that anybody could or should be expected to follow, but it is there and she abides by it strictly. She's one of the most wonderfully well-crafted characters in the series, to be honest, and it's sad that she doesn't get more respect than she does. And I'd say she's damn good at the game - SHORT term. Her biggest problem is she never takes any sort of long term plan into account and it comes back around.