What’s important is to not be “one of those people”, therefore the Democratic Party National Committee is selling bumper stickers that read “Not A Republican”. Because that’s all you need to say.
P.S. For example, liberal opinions on drones and the jihadi prison in Guantanamo changed once The Leader’s tribe changed. “Not A Republican” means it is now good policy.
Not a Republican works for me too, but I’d revise it to read, … but I vote like one.