Last weekend I attended the Shangri-La Dialogue, an annual gathering of Asian, European, and American defense and military officials and strategic experts in Singapore hosted by the London International Institute of Strategic Studies. China sent a large and well-disciplined contingent of People’s Liberation Army officers, government officials, and think tank experts who were instructed what to say in the various sessions.

The Chinese were very much on the defensive over their country’s provocative actions in the maritime disputes in the East China and South China Seas. The People’s Liberation Army (PLA) Vice Chief of the General Staff used his speech to complain about the speeches by Japanese Prime Minister Shinzo Abe and American Secretary of Defense Chuck Hagel criticizing China (Abe obliquely and Hagel bluntly) for worsening regional tensions. But Abe and Hagel were not the only voices raised against China’s unilateral approach to maritime territorial disputes. During the sessions, participants from many other countries pressed China to clarify its expansive “Nine-Dash Line” claim to the entire South China Sea, to finally conclude a Code of Conduct, and to get in step with international law.

The negative feedback showed that China was paying a reputational price for its actions, information one hopes will be reported back to the higher-ups in Beijing and cause them to reconsider their approach to the maritime disputes.

A central topic of conversation during meals and coffee breaks was the puzzle of why the Chinese government, already embroiled in tense maritime controversies with Japan and the Philippines, had elected to pick a third fight with Vietnam, a country that had been negotiating flexibly with it. A Chinese army officer confirmed my assumption that the decision to send Haiyang 981, the massive new deep sea drilling rig, to drill for oil in a location 130 miles off the Vietnamese coast must have been made at a high level and could not have been made by the oil company on its own.

But what was the strategic logic of China’s move? Was it a ploy to test the reactions of Southeast Asian countries? The ASEAN ministerial meeting a few days after the dispatch of the oil rig mustered only a very limp statement; a Singaporean official told me that during the meeting Beijing conspicuously called delegates on their cellphones to urge them not to embarrass China. Or was it designed to show Asian countries that they couldn’t count on the United States to protect them? The U.S. has limited options when countries like Vietnam are not formal allies. Could it simply be that having acquired the advanced capacity for deep undersea drilling, Chinese leaders felt compelled by public opinion to put it to use? Many Chinese have been frustrated because while other countries have drilled hundreds of wells in the South China Sea, China had yet to drill one. As one Chinese researcher, who also was trying to figure out why the government was starting fights with a number of its neighbors at the same time, put it to me, “These actions carry some international risks, but they help Xi Jinping at home.”

The international costs of China’s action could go beyond the heightened suspicions about PRC intentions expressed at the Shangri-La Dialogue. A Vietnamese expert told me over breakfast that his government was contemplating taking China to an international court as the Philippines has already done, and was likely to ramp up military cooperation with the U.S. too. China’s assertiveness has already sparked violent anti-Chinese protests in Vietnam and potentially could endanger ethnic Chinese in other Southeast Asian countries with a history of anti-Chinese sentiment.

I came away from the Dialogue disturbed by the signs that the Xi Jinping administration was willing to tolerate a higher degree of tension with its neighbors than in the past. Picking fights with smaller neighbors is a cheap way for Xi to strengthen his authority with the PLA and other interest groups and make himself popular with the nationalist public. To change Xi’s calculus, the U.S. needs to work more actively with Vietnam, the Philippines, Japan, and other Asian countries to raise the costs—for China’s security as well as its reputation—of regional bullying.