An important state-run newspaper in China ran an editorial hinting that the Chinese would not back North Korea if the latter launched missiles at Guam.

The Chinese daily, Global Times, often reflects the thinking of top Chinese leadership. 

Time:

China should remain neutral if North Korea launches an attack that threatens the United States, a Chinese state-run newspaper said on Friday, sounding a warning for Pyongyang over its plans to fire missiles near the U.S. Pacific territory of Guam.

The comments from the influential Global Times came after U.S. President Donald Trump stepped up his rhetoric against North Korea again on Thursday, saying his earlier threat to unleash "fire and fury" on Pyongyang if it launched an attack may not have been tough enough.

China, North Korea's most important ally and trading partner, has reiterated calls for calm during the current crisis. Beijing has expressed frustration with both Pyongyang's repeated nuclear and missile tests and with behaviour from South Korea and the United States, such as military drills, that it sees as escalating tensions.

"China should also make clear that if North Korea launches missiles that threaten U.S. soil first and the U.S. retaliates, China will stay neutral," the Global Times, which is widely read but does not represent government policy, said in an editorial.

"If the U.S. and South Korea carry out strikes and try to overthrow the North Korean regime and change the political pattern of the Korean Peninsula, China will prevent them from doing so," it said.

North Korea's state-run KCNA news agency said on Thursday its army would complete plans in mid-August to fire four intermediate-range missiles over Japan to land near Guam.

Trump said North Korean leader Kim Jong Un was not going to get away with his "horrific" comments and disrespecting America.

This is an unusual move by the Chinese, who are rarely so explicit in telegraphing their response to events in the region.  It will certainly make Kim think twice about launching his missiles if the Chinese will not back his play.

But the explicit warning to Trump against regime change should also be heeded.  The Chinese crave regional stability, and regime change in North Korea would drastically affect their economy.  There would also be the potential for hundreds of thousands of refugees to stream into China over their border with North Korea. 

The question then, for Trump and his advisers, is, would military action cause more problems than it would solve?  China has signaled that taking out North Korean missiles and nukes in response to an attack by Kim would be acceptable as long as the attack were limited in scope and duration and didn't result in a regime change that would place an unfriendly government in power.  This doesn't guarantee that Kim won't go off the deep end and launch nuclear missiles at the U.S. and our allies.  But it certainly puts Kim on notice that his wild rhetoric about attacking the U.S. will result in disaster for him and his country if he tries to put his words into actions.