They started off as ideological enemies. Mark Rosenberg pioneered the public health approach to preventing gun violence and opened a branch of the CDC to fund that research. Jay Dickey, the "NRA's point man in Congress", pushed a ban on CDC funding for gun violence research that lasted 20 years – and got Rosenberg fired. On this episode of Top of Mind, we tell the unlikely story of their friendship and what it can teach us about reducing gun violence in America.