A new arsenal of drones and satellite-guided weapons is changing the nature of warfare. America and its NATO allies possess these high-tech weapons, but smaller countries want them, too. Here's an inside glimpse of how the process of technology transfer works. David Ignatius says these weapons are so good that they can become addictive. They make possible precise acts of war that, in another time, would be called "assassination." The 'laws of war' may sound like an antiquated concept in this age of robo-weapons. But, in truth, a clear international legal regime has never been more needed.