The ultimate proof of generalship, Sun-Tzu observed nearly two millennia ago, is the ability to defeat an opponent without fighting. How did one go about convincing opponents that their cause was hopeless and that they were doomed to defeat, in an era before nuclear weapons?

By striking at the psychological will of opponents to resist — whether by displays of overwhelming might, undermining of their home fronts, or luring them into disadvantageous ground.

Fast-forward to the 21st century, and we find that the People's Republic of China has updated Sun-Tzu’s playbook. The People’s Liberation Army has issued regulations regarding “political warfare” to be conducted by the General Political Department — one of the four general departments that manage the army. These regulations highlight the “three warfares”: legal warfare, public opinion warfare, and psychological warfare, reflecting modern ways of ensnaring and defeating opponents without having to engage in combat.

Legal warfare, or lawfare, involves the use of national and international law to constrain and restrict an opponent’s ability to wage war. Whether it is raising doubts about whether one could legally fire missiles at Mullah Mohammed Omar’s convoy or debating the legality of drone warfare, it is clear that the courts are another battlefield in modern warfare.

Meanwhile, in the struggle to mold perceptions worldwide, China has established a global 24/7 news presence through such state-owned media outlets as the Xinhua News Agency and China Central Television. Both of these support the broader effort to influence military and civilian decision-makers, the ultimate focus of psychological warfare.

Too often, we associate psychological warfare with tactical actions, e.g., leaflets and loudspeakers. Indeed, elements in the U.S. military now prefer the term “military information support operations” over “psychological warfare.”

By contrast, the Chinese view of psychological warfare is far broader and is akin to perception management. In pressuring Japan over the Senkakus, for example, Beijing employs civilian law enforcement vessels, rather than military vessels, to underscore its demands, and highlights the history of Japanese aggression to try to gain support from Japan’s neighbors. In the recent disputes between the Philippines and China over Scarborough Shoal, the Chinese curtailed tourism to the islands and imposed additional inspections on agricultural imports, reminding Filipinos of China’s economic, as well as military, weight.

Which is not to say that China doesn’t employ military means. The recent incursion into India, with a Chinese force entering Indian territory, staying there and being resupplied, highlights the PLA’s presence along the Indian border.

At the same time, it signals other states of China’s willingness to engage in brinkmanship. Crossing the border of a nuclear-armed neighbor, after all, is not something to be taken lightly.

Perhaps the most important future battlefield for psychological warfare, though, is the Internet. The ongoing drama with Edward Snowden is probably seen as a prototypical case of (self-inflicted) psychological warfare, as the world shifts its view of the United States from guardian of the Internet to the world’s biggest rogue state.

Not surprisingly, China (as well as Russia and other like-minded states) are seizing the opportunity to expand national sovereignty into cyberspace. From their perspective, the best place to wage psychological warfare is the digital world of the Internet. At the same time, it is the most important place to defend the Chinese from psychological warfare, hence the “Great Firewall of China.”

Sun-Tzu probably would approve.

- Dean Cheng is a research fellow in the Heritage Foundation’s Asian Studies Center.