With unprecedented intimacy and frequency, Americans are becoming witnesses to murder.

With the videos of beheadings and the footage of black people being murdered by police, we’ve begun watching real people die violently in real time, often from the palm of our hands or from the screens in our laps. Most recently, we streamed the disturbing body camera footage of Samuel DuBose’s murder on our phones. We watched video of Tamir Rice’s death, transforming untold scores of people surfing social media into witnesses of the real-life murder of a child. We saw in unedited and gruesome detail the beheadings of innocents at the hands of extremists.

By now, almost all of us are witnesses to a murder. Many of us have seen more than one murder. Some of us have watched dozens.