When I saw the title on the 'Soldier/mercenary/mission' entry, another story popped into my mind. I can't remember where I read it, but maybe one of you has read it and remembers.
Story is about a real UN Peacekeeping Force, one that has the will and authority do really get things done. Part of the story is a graduating class on a field trip and being told about how the Force came to morph into what it is now, from what it used to be. The other part is a flashback to the incident that was the turning point in that evolution. It involved a terrorist, hostages, an atomic bomb, a deadman switch tied to the heartbeat of the villain. Was a good story and I want to read it again if I can find it.