The United States has not embraced any such treaty limiting the development of robots and drone for military use. But the United States would be serving its own strategic interests if it did. The odds that the United States will win such a race, considering the rate at which the cost of creating drones is dropping, is low. Better to buy into a global treaty now, while you still can.
Recently, an open letter entitled “Autonomous Weapons: an Open Letter from AI & Robotics Researchers” was released at the International Joint Conference on Artificial Intelligence in Buenos Aries on July 28, 2015. The letter spells out the basic terms for such an international treaty. 
