The White House released their International Strategy for Cyberspace document. The document says that the U.S. has an inherent right to self-defense. It says that an attack would be a last resort if diplomatic channels fail. It also emphasizes the desire to catch cybersecurity threats early, so that corporations and agencies are at least less at risk from hackers. The policy also emphasizes that an implemented warning system is needed to catch cyber-threats early and prevent them from happening early, Ars Technica reports.”]
Source: https://gizmodo.com/white-house-says-theyll-attack-if-enemies-hack-5802892