Facts

That really depends on the party. Facts matter when you want to get a point across or possibly back up your arguments. However, no matter what kind of facts you present, it won't matter to someone who refuses to believe you. What I mean by that is there are people who are so deep into their own information/ belief that they won't care what kind of facts you give because it will go against everything they believe in. Change can scare people and if you went through your entire life believing one thing just to have somebody tell you it's wrong and they present "facts" and "proof. Well then you might just reject it.

Yes facts matter to most people, but it won't matter to those who don't want to listen.