U.S. war planners have examined scenarios for North Korea that
begin with Kim Jong Un's regime collapse as a result of an
assassination or US military strike. As the country descends into
chaos, U.S. forces would try to destroy weapon systems capable of
delivering a nuclear warhead against South Korea, Japan or Guam.
The U.S. Joint Special Operations Command has a long-standing
mission to secure “loose nukes” and has trained to enter the North
to take control of its nuclear weapons facilities before rogue
commanders could pirate these weapons to international arms
bazaars. But because the sites are thought to be near China’s
borders, it is likely that Chinese special forces would beat U.S.
forces there. As Gen. Raymond Thomas, a former head of the Joint
Special Operations Command, has warned, trying to secure North
Korea’s nuclear weapons would result in a “vertical track meet”
between Chinese and U.S.-South Korean forces. Unaware of each
other’s presence, they could end up in a firefight and mistake
accidental engagement for an intentional ambush requiring
full-scale retaliatory nuclear war.
Another possibility is that, after a regime collapse, North
Korean refugees would pour into China. Fearing its own instability,
China could send troops into North Korea and establish a buffer
state between it and South Korea. Under pressure from its
population to liberate those who have lived under the most brutal
regime on Earth, the South Korean government could also send troops
marching north. Because U.S. troops and aircraft stationed in South
Korea are integrated with South Korean troops in operational
military plans, American and Chinese troops would then engage one
another directly, as they did in 1950, again resulting in an
escalation to a full-scale nuclear war.
http://inhomelandsecurity.com/china-usa-history-war/
http://www.straitstimes.com/opinion/flashpoints-that-could-ignite-a-us-china-war
https://www.washingtonpost.com/posteverything/wp/2017/03/31/how-trump-and-chinas-xi-could-stumble-into-war/
