North Korean leader Kim Jong Un, left, meets Chinese President Xi Jinping in Dalian, China, in May 2018. (Korean Central News Agency/Korea News Service/AP)

As President Trump meets North Korean leader Kim Jong Un in Hanoi this week, what is Beijing’s role in the potentially game-changing diplomacy around the Korean Peninsula? Research on Chinese strategic thought helps explain why Beijing’s policy did not get as tough on North Korea as external observers had hoped — but also why China is not simply adopting a pro-Pyongyang stance now.

Since North Korea detonated its first nuclear device in 2006, the United States and its partners encouraged Beijing to reel in its wayward ally after each major nuclear and missile test. China gradually supported tougher United Nations sanctions to deter further North Korean provocations that might precipitate a military conflict. Yet Beijing stopped well short of applying pressure that could destabilize the North Korean regime. Kim Jong Un accelerated his country’s nuclear and missile tests, then claimed in November 2017 that North Korea had achieved “the great historic cause of completing the state nuclear force.”

Once Trump announced in March 2018 that he would meet Kim for the first-ever U.S.-North Korea summit, Beijing appeared to move quickly to close ranks with Pyongyang. President Xi Jinping has hosted Kim in China four times in the past year, after the Chinese and North Korean leaders had not met even once since both consolidated power in 2012.

With the United States moving away from “maximum pressure” and South Korean President Moon Jae-in pursuing peace diplomacy toward Pyongyang, many analysts expect China to increase its geopolitical support of North Korea while advocating sanctions relief, trade and investment.

But Beijing’s approach toward North Korea does not vacillate between hard line diplomacy and friendly engagement. Instead, it opts for a middle road guided by four Chinese foreign policy norms.

1. China focuses on stability

North Korea’s sensitive geography — and the history of Asia’s regional wars — motivates Chinese strategists to avoid conflict on China’s doorstep. When the United States was discussing a “bloody nose strike” against Pyongyang, China sought to prevent “fire and fury” escalation by urging restraint and not provoking Trump.

China is North Korea’s largest trading partner and wants economic benefits to cross the Yalu and Tumen rivers. Beijing’s strategy is to address North Korean internal problems before nuclear pollution, refugees and illegal activity spill over China’s border.

China provides much of its neighbor’s oil, and data on fuel prices in North Korea suggest that Beijing adjusts its economic pressure according to interests in stability, rather than according to strict enforcement of U.N. sanctions. Chinese officials regularly assert that sanctions should not be a tool of regime change but a means to encourage a political resolution through negotiation.

2. Beijing resists “containment”

Beijing supports a formal peace on Korea. But it wants to prevent a unified peninsula that is pro-United States or heavily influenced by Japan. Beijing might use its influence over Pyongyang as a bargaining chip with Washington — such as in the current trade dispute, or to demand a reduction in support of Taiwan. But China’s policy is better understood as a strategy to avoid geopolitical encirclement.

In 2016 and 2017, Beijing put Seoul under coercive economic pressure to reject the installation of THAAD missile defenses in South Korea, apparently considering any upgrade of U.S. military capabilities or alliances as a move to contain China. Now that attention has shifted from missiles to summits, Beijing aims to stay relevant and involved with diplomacy around the Korean Peninsula so that Pyongyang does not use its “new relations” with Washington to hedge against China. Meanwhile, if the two Koreas make further progress toward peace, Beijing would consider that justification for a drawdown of U.S. forces in Asia.

3. Beijing demands respect for regional order

Chinese visions of regional order are key to understanding Beijing’s policies. Foreign Minister Wang Yi claimed China’s proposal — that Pyongyang halt nuclear testing in exchange for a freeze in U.S.-South Korea military exercises — was the “right prescription” that allowed “for the improvement of inter-Korean relations.”

Previously, Beijing hosted nuclear negotiators from the Koreas, Japan, the United States and Russia. Although Six Party Talks have been suspended for a decade, China continues to present itself as the responsible regional arbiter, offering the “correct” course of action.

Beijing may appear to be Pyongyang’s staunchest supporter but demands deference to a traditional hierarchy and punishes North Korea if it causes China to lose face. After Pyongyang conducted nuclear and missile tests while Xi was engaged in high-profile international and party meetings, Beijing withheld political exchanges and implemented sanctions more strictly.

Since North Korea’s suspension in testing, Kim has frequently visited China to consult with Xi, but the Chinese leader has yet to make a return visit. Chinese media coverage of these meetings stresses Xi’s seniority and authority, and Kim’s gratitude and eagerness to learn. The diplomatic imagery conjures up ancient tributary relations when neighboring elites would travel to pay respects to the Chinese emperor.

4. China pursues reciprocity with neighbors

Beijing maintains that North Korea has “legitimate security concerns” but has not issued Pyongyang a blank check on security or economic policy. In exchange for continued support, Beijing expects North Korea to abstain from nuclear testing and to pursue some Chinese-style economic reforms. China’s leaders have shown a certain willingness to absorb costs in dealing with Pyongyang to keep a ceiling on anti-China sentiment in North Korea and play the long game on the peninsula.

When regional tensions were high, Beijing prioritized relationships in Pyongyang, using party-to-party ties and the attractive power of China’s enormous and proximate economy. This contrasts to the U.S. emphasis on U.N. resolutions and domestic laws regulating sanctions. Now that tensions have eased, rather than put all its weight behind Pyongyang, China is supporting the Panmunjom Declaration on inter-Korean cooperation.

China’s consistency has implications for U.S. alliance coordination

Beijing’s policy adheres to its own long-standing foreign policy norms, not international law or calls to hold North Korea accountable. China’s consistent approach suggests that it is difficult for eye-catching summits to be game-changers. If Washington, Seoul and Tokyo seek a coordinated strategy on North Korea, understanding strategic thinking in Beijing is essential.

Leif-Eric Easley is associate professor of international studies at Ewha University in Seoul. His research focuses on trilateral cooperation among South Korea, Japan and the United States on engaging China, Myanmar and North Korea.