Be honest. Have you ever been willfully ignorant in a political debate, here or elsewhere? If so, why? Did you think it was necessary to get your point across? Did you think the person you were debating was introducing information that was irrelevant to the discussion? Did you have a personal attachment to topic that you felt was threatened by the information you were ignoring?
In addition, when you realize someone else is being willfully ignorant, how do you respond?