The outcome of the escalating tension between the US and North Korea will depend on what their two notoriously erratic leaders -- Donald Trump and Kim Jong-un -- opt to do.

But there certainly are more factors and variables in determining the future course of events, among which China should top the list.

The fact that Trump held a telephone conversation with President Xi Jinping over the weekend -- despite the lack of a breakthrough -- is evidence that China has a key role to play in defusing the tension.

As the sole remaining Cold War ally of the communist North, China holds unparalleled influence over Pyongyang. China is the North’s largest trading partner and benefactor, which means the North cannot survive without the supply of oil and other necessities from its neighbor.

China, which fought alongside North Korea in the Korean War, also wants to use its alliance with North Korea as leverage in dealing with the US as the two superpowers battle for hegemony in the region and beyond.

Against such a backdrop, the Beijing government used to stand in the way of the UN imposing sanctions against the North’s nuclear and missile provocations. Even when it had given consent to a sanctions resolution, China did not do all that it could do to plug loopholes such as illegal border trade with the North.

As tension grows over the North’s tests of intercontinental ballistic missiles and the US’ hard-line stance against the country, China is seen bolstering its image as the main patron of the North Korean regime.

Chinese President Xi Jinping called the alliance with North Korea one “formed by blood” during the Korean War. As the US and North Korea were openly trading threats of a pre-emptive strike, Xi employed a slogan praising the Chinese People’s Army’s participation in support of the North and victory in the “anti-US war.” That certainly is a veiled warning that Beijing will do the same in the event of another war on the Korean Peninsula.

Nevertheless, under pressure from the US, which had publicly talked about trade retaliation against Beijing, China gave a “yes” vote to the UN’s latest resolution against North Korea. That, however, should be the start, not the end, of what China can do to defuse the escalating crisis.

Basically, China does not want a radical change in the geopolitical situation of the region. The state-run Global Times made it clear in a recent editorial, saying that “China does not want to change the status quo of the areas where China’s interests are concerned.” In that case it needs to do something on its own.

First and foremost, China should persuade or pressure North Korea to stop escalating tension. What’s important is to make sure the North does not test more nuclear devices or missiles. Also urgent is to keep Pyongyang, which has threatened to fire ballistic missiles into the waters around Guam, from carrying out such a provocative act.

In relation to the matter, China gave an appropriate warning. The same Global Times editorial said China should make it clear that if North Korea launches missiles that threaten US soil, and the US retaliates, China would “stay neutral.” In other words, if the North initiates a war, it should deal with the consequences on its own.

There is no doubt that a war between the US and North Korea will result in the fall of the communist regime and a pro-America unified Korea at China’s doorstep. This alone is good reason for China to dissuade North Korea from starting a war against the US.

China would not be happy either if a nuclearized North Korea prompts South Korea and Japan to bring US tactical nuclear weapons or seek their own armament to counter threats from the North. A nuclear-free North Korea serves Beijing’s interests.

All in all, China has more to gain than lose by reining in North Korea. It should take actions to use its influence on Pyongyang to defuse the current crisis and eventually seek a resolution of the North Korea problems. First steps could include sending a special envoy to Kim Jong-un and taking the initiative to reopen the six-party talks.