Secretary John Kerry went to Beijing to again lecture his hosts about the need for China to pressure North Korea over the latter’s nuclear program. As expected, his mission failed. The Xi government again proved unwilling to threaten the survival of the Kim dynasty.

Immediately after Pyongyang’s fourth nuclear test Kerry attacked Beijing’s policy: it “has not worked and we cannot continue business as usual.” Even before Kerry arrived the PRC made clear it disagreed. “The origin and crux of the nuclear issue on the Korean Peninsula has never been China,” said a Ministry of Foreign Affairs spokeswoman: “The key to solving the problem is not China.”

While he was in Beijing she cited the behavior of other parties as “one major reason why the denuclearization process on the peninsula has run into difficulties.” Beijing officialdom has shown plenty of irritation with the Democratic People’s Republic of Korea, but China has demonstrated it has yet to be convinced to destroy its own ally and strengthen America’s position in Northeast Asia.

Kerry made the best of an embarrassing situation when he announced that the two sides agreed to an “accelerated effort” by the UN Security Council to approve a “strong resolution that introduces significant new measures” against the DPRK. No one should hold their breath as to the nature of those “measures,” however.

Foreign Minister Wang Yi echoed Kerry in supporting passage of “a new resolution,” but added the devastating caveat: “In the meantime, we must point out that the new resolution should not provoke new tensions in the situation, still less destabilize the Korean peninsula.” Wang explained that “Sanctions are not an end in themselves” but should encourage negotiation, not punish.

As I point out in National Interest: “If Kerry wants the Chinese to follow U.S. priorities, he must convince them that America’s proposals advance Chinese interests. Which means explain to them why they should risk destroying their one military ally in the region, with the possibility of creating chaos and conflict next door and adding the entire peninsula to America’s anti-China alliance network.”

Good luck.

In 1950, the PRC went to war with the U.S. to preserve the North Korean state and prevent American forces from advancing to the Yalu River. Even today Beijing wants to see a united Korea allied with Washington about as much as it desires to have a nuclear North Korea.

Indeed, even without a U.S. garrison, a more powerful ROK would pose a challenge to the PRC. Moreover, Beijing’s favored economic position in the North would disappear as South Korean money swept away Chinese concessions.

Worse, the process of getting to a reunified Korea likely could be disastrous. Nothing in the DPRK’s history suggests a willingness to gently yield to foreign dictates. In the late 1990s the regime allowed a half million or more people to starve to death. Irrespective of China’s threats, Kim Jong-un might say no and continue in power, irrespective of the human cost.

If China ended up breaking a recalcitrant Kim dynasty by sanctioning oil and food, the result could be extraordinary hardship and armed factional combat followed by mass refugee flows across the Yalu—multiply the desperation and number of Syrians heading to Europe. Then toss in loose nuclear weapons and a possible South Korean/U.S. military push across the Demilitarized Zone to force reunification.

The result would be a first rate nightmare for Chinese President Xi Jinping. So, explain to me again, Secretary Kerry, why my country should ruin its geopolitical position to further Washington’s ends?

If John Kerry’s private message was the same as his public pronouncements, he had no hope of winning Chinese support for taking decisive action against the DPRK. Next time he visits he should employ the art of persuasion—or stay home.