Short of an apocalyptic event or a total sociopolitical revolution, mass killings will not likely cease or significantly diminish. Without fundamental change, there is little hope.
Why? Because complex problems requires complex solutions, and complex solutions are rarely if ever satisfactorily offered by one or the other faction, alone. Consider just four of the explanations typically offered, all of which have (at least on occasion) some merit:
1. Nihilism/Disbelief (conservative explanation - in my view, this is the root from which the remaining problems sprout)
2. Gun accessibility (liberal explanation)
3. Racism (liberal explanation)
4. Fatherless children (conservative explanation)
Aside from corruption in our political system, a huge impediment to a holistic solution is ideological dogmatism, which prevents each side from recognizing the merits of the other's diagnoses and prescriptions.
