Updated

In justifying U.S. involvement in Libya, the Obama administration cited the "responsibility to protect" citizens of other countries when their governments engage in widespread violence against them. But in the realm of cyberspace, the administration is ignoring its primary responsibility to protect its own citizens when they are targeted for harm by a foreign government.

Senior U.S. officials know well that the government of China is systematically attacking the computer networks of the U.S. government and American corporations. Beijing is successfully stealing research and development, software source code, manufacturing know-how and government plans. In a global competition among knowledge-based economies, Chinese cyberoperations are eroding America's advantage.

The Chinese government indignantly denies these charges, claiming that the attackers are nongovernmental Chinese hackers, or other governments pretending to be China, or that the attacks are fictions generated by anti-Chinese elements in the United States. Experts in the U.S. and allied governments find these denials hard to believe.

Three years ago, the head of the British Security Service wrote to hundreds of corporate chief executive officers in the U.K. to advise them that their companies had in all probability been hacked by the government of China. Neither the FBI nor the Department of Homeland Security has issued such a notice to U.S. executives, but most corporate leaders already know it.

Some, like Google, have the courage to admit that they have been the victims of Chinese hacking. We now know that the "Aurora" attack (so named by the U.S. government because the English word appears in the attack software) against Google in 2009 also hit dozens of other information technology companies—allegedly including Adobe, Juniper and Cisco—seeking their source code. Aurora wasn't an isolated event. This month Google renewed its charge against China, noting that the Gmail accounts of senior U.S. officials had been compromised from a server in China. The targeting of specific U.S. officials is not something that a mere hacker gang could do.

The Aurora attacks were followed by systematic penetrations of one industry after another. In the so-called Night Dragon series, attackers apparently in China went after major oil and gas companies, not only in the U.S. but throughout the world. The German government claims that the personal computer of Chancellor Angela Merkel was hacked by the Chinese government. Australia has also claimed that its prime minister was targeted by Chinese hackers.

Clarke was a national security official in the White House for three presidents. He is chairman of Good Harbor Consulting, a security risk management consultancy for governments and corporations.

Click to Read Clarke's Full Column at wsj.com