Violence is a virus. It can be transmitted by exposure just like hepatitis, AIDS, or the common cold. The thing about violence is that it grows from the smallest thought, and begins to take root to greater depths. Violence is not acted out against another person; in fact, it has nothing to do with other people. It is a thought pattern within each individual. Violence is viewing another's misfortune for entertainment, violence is the acceptance of murder because the victim is not of your nation, and I will even go on to say that violence is valuing yourself over someone else because they lead a different walk of life. We all know the parable of The Good Samaritan. Walking by the wounded man is a form of violence. No, the first two travelers were not the instigators of the injury, but they were just as accountable nonetheless. Violence is not a physical, but rather a spiritual entity. Like a virus, it always begins invisibly, takes root within the host, and propagates before it even shows its first symptom. It can be as simple as an attitude or thought. Violence always develops in the same pattern: detachment, passiveness, indifference, egocentricity, entitlement, and only then does it progress to physical violence.
In contrast to violence, compassion is a seed. It requires cultivation. Cultivating compassion is much more difficult than becoming a host to the violence virus, because compassion doesn't "take hold" like violence. It requires conscious cultivation and must be nourished to germinate. Nurturing your mind with wholesome entertainment, interactions, and thoughts are necessary for growing compassion.
I usually do not address potentially political topics because people will invariably think of a ridiculous hypothetical situation in which to trap you into contradicting your own beliefs. I am not implying that I WILL always take the path of compassion, I am attesting that compassion IS always the right path to take.
Roots of violence and compassion are already within all of us. How deep they grow is up to you.....