American presidential campaigns are not the only targets. China is significantly boosting its capabilities in cyberspace as a way to gather intelligence and, in the event of war, hit the U.S. government in a weak spot, U.S. officials and experts say. Outgunned and outspent in terms of traditional military hardware, China apparently hopes that by concentrating on holes in the U.S. security architecture -- its communications and spy satellites and its vast computer networks -- it will collect intelligence that could help it counter the imbalance.

President Obama, who is scheduled to visit China next week, has vowed to improve ties with the Asian giant, especially its military. But according to current and former U.S. officials, China's aggressive hacking has sowed doubts about its intentions.

"This is the way they plan to thwart U.S. supremacy in any potential conflict we get into with them," said Robert K. Knake, a Council on Foreign Relations fellow. "They believe they can deter us through cyber warfare."

Some U.S. cyber policy experts such as James A. Lewis, a senior fellow with the Center for Strategic and International Studies, acknowledge that the problem cannot be solved without international engagement. At the same time, Lewis said, "I'm not going to get upset about China spying on us, because we spy on them."

"The only thing I'm going to get upset about," he said, "is if we don't do better than them."

The DoD hacks get the most media attention, but the Chinese activities expand way beyond DoD. There are compromises all over the place on The Hill, in the think tanks, lobby houses, and key law firms. All the targets in the political/policy space are vastly softer than military and intelligence targets. Most of DC is owned.