In one sense I was amazed that no one had already offered what I believe to be the 'key' answer. (Now, isn't that what we all think?!?!?)
I think every answer already given is pretty much right on the mark. But in order to bring a greater degree of peace and stability to the world, each and every one of them must by necessity go one more step. Else the problem is identified, but not solved.
Agreeing that God MUST be introduced/re-introduced into our consciousness if we really are to come up with the 'cure all' answer, we have to look to God, Jesus and the Bible in order to identify and self model the mandate each provides.
I draw your attention to the fact the entirety of Biblical teachings surrounds and distinctly embraces the one and only thing which will 'clear the slate' and help us begin again to become all whom we might be - as well as ensure we've chosen correctly our Eternal destination is... forgiveness.
After we've identified any and all of the principle faults, the next, thus worse fault of all is our lack of forgiveness in all these issues. True, to the core, forgiveness. That is mankind's biggest fault. Forgiveness is the beginning stage of all cures. Without it, not only will we remain in and among the other faults noted, but we'll open the door to further infection within by them and the results they bring forth.
Recognize though, that by forgiving someone - you don't necessarily have to have them over for tea and cookies. Moral, civil and criminal faults must be dealt with under the communal standard of law and justice.
But YOUR OWN HEART must be cleansed - not in vengeance, but with release. The only way to begin the route to wholly release is to forgive. After all, the definition of 'forgive' is to 'not allow (whatever or whomever) to become influential in your future'. The only way for that to happen is to release - not retain a heart of even legal and proper vengeance.
It is possible then, to even send someone to the Gallows and know there is forgiveness in your heart. But that's another story.
You might find, - www.areyousavedyet.com - or - www.howtodefinelove.com - of interest to you.