Already, the U.S. and other militaries are doing research into ways armed robots could do much of the work that is today performed by manned warships and submarines, especially in difficult environments like the Arctic. But a newwhite paper from the United Nations Institute for Disarmament Research, released last month, warns that ever-smarter naval robots could make for very choppy waters in places where the United States, Russia, and other nations have a growing presence and competing interests.