The new year has not started off well at all for China, what with its stock market plunge and the latest provocation by not-so-neighborly North Korea. Regardless of its veracity, the announcement of a hydrogen bomb test constitutes a major dis to China, especially in light of recent efforts by China to improve ties between the two sides.

I agree that China can play a significant role in exerting more pressure on North Korea, including through its economic leverage and support of U.N. sanctions. However, expectations of what China can or cannot do to elicit a positive change in North Korea’s behavior need to be tempered against the fact that relations between these two countries have changed under their current leaders.

Kim Jong-un’s actions, including this week’s announcement, indicate a desire for North Korea to be respected as a nuclear power and an unwillingness to be a junior partner to China. Chinese president Xi Jinping has moved away from his predecessors’ practice of staunchly standing by North Korea as an historical ally; three years into his term as Chinese Communist Party general secretary, he has not yet met with Kim, opting instead to foster closer ties with South Korea.

China’s open criticisms of North Korea’s actions, especially the latter’s repeated nuclear tests, reflect not only thinning patience over North Korea but also frustration over a diminishing ability to gain accurate insights into Kim’s motivations.

The North Korea nuclear issue is also a prime example of a “cooperation conundrum” for China and the United States. Both share a common interest and goal in seeking denuclearization of North Korea and the Korean peninsula. But their approaches have differed, largely due to diverging strategic concerns.

U.S. concerns about the threat of a nuclear-armed North Korea to its Asia allies—especially Japan and South Korea—and to U.S. soil have been a key driver behind efforts to strengthen security cooperation, such as the recently revised U.S.-Japan defense guidelines (reflecting Japan’s more proactive defense posture) and a possible U.S. Terminal High Altitude Area Defense (THAAD) system in South Korea. These developments have left China jittery about their effects on its security and strategic deterrence.

China itself faces a delicate balancing act. Repeated brinksmanship by Kim may encourage China to undertake or support a further mix of incentives (e.g. diplomacy) and especially disincentives (e.g. sanctions) to rein in North Korea. Yet, it may still hold back, due to worries about overplaying its hand and forcing North Korea into a corner, eliciting instability on China’s border, and possibly leading to eventual Korean reunification and a U.S. ally on China’s doorstep.

Any discussions between the U.S. and China on coordinating efforts to stem the North Korea nuclear problem will need to take those concerns into account. Another question for the U.S., China and the international community is whether North Korea denuclearization is still a realistic goal in the foreseeable future. With this latest nuclear test—North Korea’s fourth—Kim appears to have answered with a resounding “no.”

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