As I've said before, a major difference between conservatives and liberals is empathy. If you can imagine how other people feel, you can put yourself in their shoes. You can begin to try to understand them, and no matter how different they are or how much you disagree with them you can't hate them completely. You empathise, and empathy makes you brave enough to fight your fear of the Other and strong enough to conquer hate. Most conservatives can't begin to understand this. They think the lack of hate is moral confusion and that fear is vigilance. To be brave is an affront, and to understand is to be weak.
This lack of empathy is dangerous. If you don't think about the consequences of your actions and how they affect other people, there is nothing keeping you from doing whatever you want. You will quite deliberately choose to take actions that will harm other people. You manipulate energy markets or sign torture memos or order the bombing of ancient nations because you don't really care what happens to the people affected by your actions. Sometimes you are able to feel some empathy when something bad happens to a person you know, such as when a friend is shot. Then you can feel the shock of his family and friends and sympathy for his pain. But in general you don't care about anyone outside your own circle, be it as small as a family or as large as a nation.
And so choices are made, and ripples of reaction fan out across the surface of the world. And the result is evil. Evil actions that rip people apart, starve children, kill nations. But that's not what the soulless ones, the ones without empathy, say. Bad things aren't consequences of callous decisions. They're the will of God, they're Satan battling God and using man as a battlefield. There is an evil miasma stalking the land, ensnaring good people into doing bad things. Or they have inferior genes. Their culture is bad and their genes are bad so bad things happen to them. It's all their fault.
We get empathy from our parents; many of us are taught that other people have feelings too, that if you hit someone else it hurts them, just like being hit hurts you. If a child is shown understanding and respect he will like and accept himself, and will be much more likely to show understanding and respect--and empathy--for others.
It's our choices that matter. What we do every minute of our lives, how we treat the people around us, and how we look at the people beyond. Who we will treat as brothers, and whom we will choose to fear. Callous people make up excuses and reasons and even ideologies to explain why the don't care about others but the reason is always very simple: They can't.
Read Evil as the Absence of Empathy by Ernest Partridge.