It is the Second Amendment and the GUNS:
Any killing is barbarian in a civil society.
With the present day wrong interpretation of Second Amendment, just any angry and upset person and petty criminals randomly kill people, like in this October First, 2017 killing in Las Vegas of 58 people and injuring 515 by 64-year-old Stephen Paddock, an ordinary American citizen.
Each time the NRA and thegun lobby blame such situations on psychological disorder of some people and terrorists acts and defend the Second Amendment.
But the psychological disorders and terrorists cannot be ruled out or banned with laws. Guns can only be controlled by revoking the Second Amendment and passing stricter gun laws, and then there will be less number of guns in homes and streets and less killings. How many more such sporadic killing incidents at our public places, in our schools, in our work places, we are willing to tolerate to come to our senses that Second Amendment was not meant as we are implementing it? The United States has the strongest Military in the world, it does not need any Militias with guns to protect it now.