Much like her elder daughter, Catelyn Stark is a character whose intelligence is seriously underrated. There’s less of an intellectual arc apparent in her story as compared to Sansa’s, as Catelyn is a grown woman, but that doesn’t mean her thinking is static. It must be said that she is one of the series’ most staggeringly unfortunate characters, as the tragic structure of her arc demands that her decisions and risks to protect her family fail and rebound upon them.
Yet lack of success does not equal lack of intelligence. Even in her mistakes and failures, it is more than possible to see that this is not a woman who didn’t think before she acted.