The Year in Ideas; Robotic Warfare

This November in Yemen, an unmanned Predator plane -- known as a drone -- blew up a car full of suspected Al Qaeda members. The plane's ''remote pilot'' sat in a trailer located miles out of harm's way. The Pentagon considers unmanned planes like the Predator perfect for ''the 3 D's'': missions that are so dull, dirty or dangerous that it's best to leave humans out of the equation. The Predator is just the start of what may well be the largest shift in military tactics since the invention of gunpowder -- a wholesale removal of American personnel from the front lines. This year at Edwards Air Force Base in California, the biggest advance yet in robotic warfare took its first flight: the UCAV, or Unmanned Combat Air Vehicle.