A year ago the Obama administration unveiled its "International Strategy for Cyberspace." The document said, among other things, that "aggressive acts in cyberspace" may be viewed by America as acts of war. "When warranted, the United States will respond to hostile acts in cyberspace as we would any other threat to our country," which may mean the use of "military force." The U.S. "has no intention of sitting quietly while corporate and governmental computer systems are attacked with impunity."
Thanks to reporting by David Sanger in Friday's New York Times, we now know that President Obama, when he signed that document, had already "secretly ordered increasingly sophisticated attacks on the computer systems that run Iran's main nuclear enrichment facilities, significantly expanding America's first sustained use of cyberweapons." This was the famous Stuxnet computer virus, developed in collaboration with Israel.
To fully appreciate the hypocrisy, you need to read the more high minded parts of that 2011 cyberspace manifesto: "The digital world is no longer a lawless frontier ... It is a place where the norms of responsible, just and peaceful conduct among states and peoples have begun to take hold." Cyberspace must be "built on norms of responsible behavior."