Serious cyberattack on ally could trigger U.S. retaliation under treaty


The United States could carry out its defense obligations under bilateral security treaties if allies including Japan suffer cyberattacks that cause physical damage, former U.S. Undersecretary of Defense for Policy Michele Flournoy has suggested.

“If there were threats in cyberspace that would actually translate into the physical world . . . it seems to me that’s a case where our mutual defense obligations would apply,” she said.

The U.S. government is increasing security steps against cyberattacks that could cause serious physical damage, such as train derailments or drinking water contamination, and has indicated its willingness to cooperate with Japan and others in tackling such serious cyberattacks, which former Defense Secretary Leon Panetta called “cyber-Pearl Harbor.”

The comments by Flournoy apparently reflect Washington’s position that serious cyberattacks against Japan could result in U.S. retaliation.

“If there was a cyberattack that caused physical damage or loss of life in one country or the other, I would think that would . . . trigger our mutual defense obligations,” Flournoy said.

She added that it would be important for the United States to discuss with its allies rule-making for cyberspace, information-sharing and cooperation to respond to different types of cyberattacks.

On a possible revision of pacifist Article 9 of the Constitution, advocated by Prime Minister Shinzo Abe, Flournoy said, “I think there should be great sensitivity to how others in the region will hear it.”