The face of America's unauthorized offshore wars has changed over the years, and these days it can most often be found watching the infrared screen of a terminal in some heavily-guarded air force base on US soil, operating heavily-armed, remote-controlled drones thousands of miles away, tasked with executing a lethal mission which usually involves one or more "collateral" casualties.
For almost five years, Brandon Bryant was one of those faces, and worked in America's secret drone program bombing targets in Afghanistan and elsewhere.
He was told that he helped to kill 1,626 people, but as time went by he felt uneasy with what he was doing. He found it hard to sleep and started dreaming in infra-red.
What made him stop? "The actual breaking point happened when we were hunting an American citizen, and they were saying he was maybe the next bin Laden. This was an American citizen - these were the people that I swore to protect. I believe that at that moment we were doing the wrong thing and that was when I decided to turn my back and walk away."
There were countless others who were happy to fill his vacant position.
Below is Brandon Bryant full interview with BBC's Witness program about his doubts and the mission that convinced him it was time to stop.