I'm going to badmouth someone who holds political views I disagree with
Why are you doing that when they haven't harmed anyone?
I don't want to be too extreme but I'm going to do it if I have to
Even if a person holds political views that are antithetical to your own, you shouldn't attempt to bad mouth that person. You should be able to disagree with someone's politics without having to attack their character. Taking the political opinions of others so personally can cause a lot of social harm and is something that should be avoided.
I see what your saying but I'm going to attack that persons character in a minute.
What are you hoping to gain from bad mouthing them? It seems like you're just trying to hurt them and there's no benefit to you.