Contrary to the tripe I've just read in the comments, gun violence existed before the country was so politically divided, even before serial numbers were required to be placed on firearms by manufacturers. 

And before firearms, or for those who couldn't afford them or find a gun to steal, violence occurred with baseball bats, clubs, knives, stones, by submerging one's opponent in water, burnings, hangings, etc.

Laws and partisanism won't fix those thousands of years of human misbehavior. 

Poverty, lack of upward mobility, poor training regarding personal boundaries, mutual respect (something lacking in many of the upstanding citizens comments I just perused), and evolution -might- help to adjust frequencies of violence. But these are HUMAN issues, and have been since before we began recording our presence on Earth.

Did Christ, Manitou or Allah blame opposition parties or inanimate objects for human frailties? No? Then maybe we're devolving, not evolving.