I don't think that most political questions pit people's actual self-interests against each other. The biggest exception of course are some policies like affirm

I don't think that most political questions pit people's actual self-interests against each other. The biggest exception of course are some policies like affirmative action where the lines of self-interest are obvious. But for many other issues e.g. drug policy and climate change there are a great deal of factual misconceptions driving policy by causing people to think their self-interests lie other than where they are. Engaging the rational mind is usually considered important in dealing with this situation because it does better with facts.