A friend of mine grew up in Mississippi. He mentioned that a handy moral guide was finding out the Klan's position on any topic, exp. politics. If you find you're in agreement with the Klan, that's a good time to stop and reevaluate everything. Every. Single. Thing. That lead to forming your opinion.
I'd say that even more reflection is required if you find yourself actually agreeing with, or hoping you'd agree with, Hitler.