Cyberattacks on U.S. networks by other nations may not always demand the same level of retaliation. Only attacks that cause major damage or loss of life should prompt similar responses, experts say. Cyberattacks are commonplace and part of a long history of international espionage, experts said Wednesday. An attack that takes down a large portion of the US electric grid or the banking system would likely require significant retaliation, they said. The CSIS panel came just days after the Department of Defense said it was prepared to use force to respond to some cyberattacks.”]