In his remarks before the House Armed Services Seapower and Power Projection Forces Subcommittee, Bryan Clark argues that American undersea dominance will increasingly be contested by competitors who are pursuing new detection technologies while growing and quieting their own submarine fleets. To affordably sustain its undersea advantage well into this century, the U.S. Navy must accelerate innovation in undersea warfare by evolving the role of manned submarines and exploiting emerging technologies to field a new "family of undersea systems."