Nobody ever does -- it's a constantly evolving field of engagement. Just teach your children to think for themselves -- and sometimes that means they are going to disagree with you pretty harshly; at a certain point, on certain things they have a right to, they have their own lives to live -- and teach them that you love them, that your family comes first and the difference between being good and "nice". And then, when they are old enough, you let them go and take their chance in this world -- because how can you talk about freedom if you won't let them go out and make their way? Oh, above all else, teach them to be well read (for understanding) and give them good books...and then let them read Das Capital and Mein Kampf and other things when you think they are ready to, and ask them what they think of it. In order to stay away from/protect oneself against evil, you have to face it and know it.