If partisanship makes us abandon intellectual honesty, if we oppose what our opponents say or do simply because they are the ones saying or doing it, we become mere political short-sellers, hoping for bad news because it's good for our ideological investment.
This duality has been reflected in classical as well as modern literature as reason versus passion, or mind versus intuition. The split between the conscious mind and the unconscious. There are moments in each of our lives when our verbal-intellect suggests one course, and our hearts, or intuition, another.