In early July, South Korea decided to allow the United States to deploy the Terminal High-Altitude Area Defense (THAAD) system. At the heart of this issue is the difference in how China and the United States view the role of South Korea and decisions related to the security and stability of the peninsula.

No matter how the wrangling over THAAD evolves, it will ignite strategic gaming as well as new and high military technology competition among major powers. Pentagon planners may be rejoicing over the ROK decision to embrace the American project, but the US will have no control over the reaction to the deployment.

Following months of assessment by a Joint Working Group, the U.S. Defense Department announced in July that the U.S. Forces Korea Command will station a Terminal High-Altitude Area Defense (THAAD) battery in South Korea “as a defensive measure to ensure the security of the nation and its people, and to protect alliance military forces from North Korea's weapons of mass destruction and ballistic missile threats.”

The U.S. Defense Department recently announced that the U.S. Forces Korea Command will station a Terminal High-Altitude Area Defense (THAAD) battery in the Republic of Korea (ROK) as a defensive measure against North Korea. But Russian and Chinese representatives have expressed concern about how THAAD could affect strategic stability, alliance relations, and global influence.

By ignoring the Chinese, Kim Jong-un has been gambling with his regime’s future. The PRC appears more ready than ever before to abandon its troublesome friend. However, inertia—and a cold-hearted assessment of interests—is likely to hold Beijing back from cooperating with the U.S. if forced to choose America over Pyongyang.

No nuclear-weapon states have given up efforts in modernizing their arsenals, although for different reasons. A commitment of no-first-use is defensive in nature, but it doesn’t exclude nuclear retaliation. Such a pledge doesn’t cripple other countries’ nuclear capabilities: It boosts confidence that a world free of nuclear weapons is eventually possible.

China regards both the U.S. and Iran as important partners, which is why Beijing played a major role in putting together the Iran nuclear deal. Implementing that plan will face challenges in both the U.S. and Iran, and China’s commitment to building a new type of major-country relationship with the US means it will continue to assist both countries to keep the deal moving forward.

One week before his Hiroshima visit, U.S. President Barack Obama said in his interview with NHK that his purpose is not to revisit the past, but to affirm the need of peace and a world without nuclear weapons. Whereas the declared message of his Hiroshima visit is denuclearization, the unspoken connotations could be more meaningful.

Obama will visit Hiroshima on May 27th when he attends the G7 summit held later this month in Japan. However, the visit may backfire and hurt Japan by touching off an inconvenient chain reaction. By fixating on the nuclear trauma while blotting out recollections of Japan’s victimization of others, Japan’s sense of its role as a victimizer has been weakened.

With the end of the nuclear security summits and major Russia-U.S. security tensions, China-U.S. nuclear security cooperation is needed more than ever. Fortunately, both governments are pursuing projects to counter nuclear smuggling, reduce the use of dangerous nuclear fuels, and augment other international institutions that counter nuclear terrorism.