Napoleon famously described China as a sleeping giant that would shake the world when it finally awoke. Well, now the giant is up and about, and the rest of us can’t help but notice. 2010, indeed, could well end up being remembered as the year when China started throwing its weight around.

Why this should be happening now, in precisely this way, is not immediately obvious. For years Chinese leaders seized every opportunity to assert that their country’s growing power posed no threat to the international status quo. Talk of the “peaceful rise” was all the rage. Chinese diplomats deftly disarmed the concerns of their neighbors in the region, reassuring anyone who would listen that Beijing would never stoop to the sorry unilateralism of those imperialists in Washington. Journalists spoke of China’s “charm offensive.”

China Rising, a 2007 book by the University of Southern California’s David Kang, began by approvingly citing a speech a year earlier by Chan Heng Chee, Singapore’s ambassador to the United States. “Dynastic China’s relations with Southeast Asia were to a large extent based on ‘soft power,'” she declared. “It was China’s economic power and cultural superiority that drew these countries into its orbit and was the magnet for their cultivation of relations.” Chan concluded her remarks by saying that “there is much optimism in Southeast Asia” about China’s growing international heft.

That optimism now seems distinctly historical. In March of this year China startled the rest of East Asia by announcing that it would henceforth regard the territories in the resource-rich South China Sea as being an area of “vital national interest,” on a par with Tibet and Taiwan. Vietnam, Indonesia, the Philippines, Brunei, Malaysia, and Taiwan all claim various islands within the region as their own, but for the past few years China had succeeded in defusing the potential for conflict by pledging to resolve these disputes through negotiation, demonstrating its seriousness by joining a nonaggression pact under the aegis of the Association of Southeast Asian Nations (ASEAN). Now, by contrast, the People’s Liberation Army Navy is aggressively patrolling the disputed waters. Chinese naval ships have seized dozens of Vietnamese fishing boats and arrested their crews.

In September the Japanese Coast Guard arrested the captain of a Chinese fishing trawler after his boat collided with two Japanese vessels in waters off the Japanese-administered Senkaku Islands, which are also claimed by both Beijing and Taipei as their own. (In Chinese they are known as the Diaoyu Islands.) The Chinese thereupon threatened the Japanese with unspecified reprisals unless the captain was released, and a wave of anti- Japanese demonstrations—the one…