In the first annual “Transactions” published by the venerable Korea Branch of the Royal Asiatic Society in 1900, James S. Gale, one of the early missionaries, wrote, “The more we read, the more we are forced to the conclusion that Korea was under a mesmeric spell at the hands of the Great Middle Kingdom.”

In refutation, H.B. Hulbert, another notable missionary, author of a classic history of Korea, argued that “the points of similarity with the Chinese are the exception and that the survival of things purely native and indigenous are the rule.”

Chinese influence over Korea, North and South, remains if anything more hotly debated today than it was when foreign observers, visiting Korea and China more than a century ago, noted the many similarities and differences. These days, debate focuses on China’s ability to persuade North Korea to forget about its vaunted nuclear and missiles program and get on with what matters most: economic development and the health and well-being of its impoverished people.

China is North Korea’s only real ally and the source of virtually all the oil as well as basic products that get into the country despite sanctions, but the North can be difficult for the Chinese. China may not object as strenuously as the Americans would like to the North’s missiles and nukes but can’t be happy about them either. Otherwise, China would have blocked U.N. resolutions condemning tests of nuclear warheads and intercontinental missiles.

The Chinese position may be complicated by the continuing quarrel over China’s inordinate trade surplus with the United States as well as constraints imposed on foreign firms in China, but China is key to keeping the lid on Kim Jong-un’s wilder ambitions. Chinese influence goes deep into the culture of both Koreas even if South Korea’s late dictatorial President Park Chung-hee curbed Chinese communities in Seoul, Incheon and Busan, among other places.

China’s role is so important that it’s unlikely the North Koreans can do too much that they have not done already by way of testing nukes and missiles. The Americans have gotten absolutely nowhere in persuading the North to give up its WMD programs, as was evident from the latest visit to Seoul and Beijing of Stephen Biegun, the nuclear envoy who was confirmed as deputy secretary of state before returning to Washington.

Biegun failed utterly to persuade the North Koreans to agree to talks during his travels, but so what if they capture global headlines whenever they conduct one of those tests? Kim knows the Chinese can always punish him by turning off the spigot on oil and other vital supplies, many of which get in despite sanctions.

The ultimate power of China’s President Xi Jinping over Kim and his regime is one reason the South’s President Moon Jae-in can afford to make concessions. The chances of Kim translating his big talk into real action, not just testing, are basically nil. In the meantime, Kim can enjoy baiting the United States with displays of “activity” around nuclear and missile facilities, most recently the Sohae site in the northwest near China.

Given the constraints imposed by Big Brother in Beijing, Kim would be smart to announce an end to his nuclear nonsense when he gives his New Year talk. Don’t hold your breath waiting for such news, but then again stranger things have happened, for both better and worse, in the twists and turns of Korean history since the Japanese surrender in 1945.

Which brings us to the unpredictable Donald Trump. Sorry to disappoint the throngs waving U.S. and South Korean flags every Saturday in central Seoul, but this guy probably is not aware of your respect, your love, for the United States. He’s just cut the small U.S. contingent in Afghanistan, and he’s pulled U.S. troops from northern Syria. Might a reduction in U.S. strength in Korea be next?

By calling for Korea to spend much more for the privilege of having 28,500 U.S. troops on bases in-country, Trump has shown how little he cares. With an impeachment trial hanging over his head, he’s got more important stuff to worry about on the way to his second campaign for president.

Which brings us back to China. Those early missionaries knew the Chinese were in Korea a long time before them. Chinese forces drove the Americans from the North in the Korean War. Don’t they need to hold back the North Koreans if they get out of hand? Korea means that much to China. Therein lies the strategic balance for peace in the region.