I think the place to start is visual, both images and raw data, information, pictures, infographics and a government campaign of education. This is where I think the middle and reason has a chance to start. Within 30 minutes of this event, Fox News and that crazy dark haired lady from the NRA was already on her soap box saying this is not about guns... But the one thing they can not argue with are images. The picture of the green Converse sneakers worked! Keep that image up. But really it needs to be even more, much more. Images of the dead children need to be on the sides of highways, in youtube ads, on TV programs showing missing arms and legs. If I were you, I'd make this documentary and get the parents to release the autopsy pictures for the public to see in commercials. It is what worked for cigarettes, and other education campaigns. Then there is data. BradyUnited data: https://www.bradyunited.org/key-statistics More people die in one day from gun shot wounds in the US than the entire year in England: https://www.usatoday.com/story/news/world/2016/06/16/gun-violence-united-kingdom-united-states/85994716/