North Korea conducted its third nuclear test Dec. 12, exploding what is paradoxically being called a "miniaturized" device that nonetheless packed a greater explosive force than those the DPRK set off in 2006 and 2009. "We can assume this is roughly twice as big in magnitude," said Lassina Zerbo of the Comprehensive Nuclear-Test Ban Treaty Organization (CTBTO), which monitored from afar the underground blast at the Punggye-ri  test site in the DPRK's northeast mountains. Pyongyang said the test was an act of self-defense against "US hostility." South Korea, which placed its US-backed military on alert after the test, said it would fast-track development of longer-range missiles that can reach the whole of North Korea. "We will speed up the development of ballistic missiles with a range of 800 kilometers," a Defense Ministry spokesman told reporters. 

China responded to the test with an unusual reprimand, summoning the North Korean ambassador to protest. The Foreign Ministry said China was "firmly opposed" to  the test, and called on Pyongyang to "refrain from any move that may further worsen the situation." The UN Security Council held an emergency meeting at which its members, including China, "strongly condemned" the test. (SCMP, AFP, Jan. 13; Reuters, Reuters, Feb. 12)

China has for the past decade maintained an equidistant stance between the two Koreas—maintaing the North as a buffer state against the US military forces in the South, but finding the South too alluring for capitalist investment to isolate. Incoming president Xi Jinping  may find Pyongyang's bellicosity both dangerous and useful. Wrote a New York Times analysis on Feb. 12:

Mr. Xi, who became head of the Communist Party and military council in November, will ascend to the presidency of the country next month. Already he has shown himself to be more nationalistic than his predecessor, Hu Jintao, displaying China's determination to prevail in the East China Sea crisis in which China is seeking to wrest control of islands administered by Japan. He has also displayed considerably more interest in China's military, visiting bases and troops...with blandishments to soldiers to be combat ready.

To improve China's strained relationship with the United States, Mr. Xi could start with getting tougher on North Korea, harnessing China's clout with the outlier government to help slow down its nuclear program. If Mr. Xi does not help in curbing the North Koreans, perhaps by privately threatening to pull the plug on infusions of Chinese oil and investments that keep North Korea afloat, he will almost certainly face an accelerated American ballistic missile defense program in Northeast Asia on behalf of Japan and other allies in the region. That would be an unpalatable situation for China.

Blogs The Interpreter:

Kim Jong Un's decision to test this week is a clear affront to the new Chinese leadership. After all, China had warned the North not to test, with outlets such as the Global Times claiming there would be a 'heavy price' to pay. And the timing of the test around Chinese New Year would have compounded the embarrassment, as Chinese netizens are pointing out. Indeed, the rise of social media and that fact that many patriotic Chinese are so openly critical of North Korea may itself help to shift the Chinese policy debate.

Xi also responded to the test by telling South Korea's president-elect Park Geun-hye that non-proliferation of weapons of mass destructions and "denuclearization" are "essential conditions" for stability on the peninsula. That was the direction the two Koreas had been going at the end of the Cold War, signing a Joint Declaration on the Denuclearization of the Korean Peninsula in 1991, following which the US removed its tactical nuclear weapons from the South at Seoul's request. But the thaw didn't last long, as the North barred the International Atomic Energy Agency (IAEA) from inspecting its nuclear faciltiies in 1993. In its post-Cold War economic crisis, the North's leaders may have simply sought to use the nuclear program as a bargaining chip to win food aid. Such aid was able to slow its nuclear drive under Clinton (with Republicans crying appeasement, of course), but US intransigence under George W. Bush only fueled the regime's radicalization —as we have blogged, repeatedly. (Chosun Ilbo, Feb. 13; NTI, IISS, Global Security)

Washington's New Cold War with China poses a further obstacle to the peninsula's denuclearization, but also makes it more of an imperative for China. Which, with luck, could win some elbow room for the Koreans to retake the initiative from the Great Powers. We know of anti-militarism voices in South Korea. The really interesting question is the potentiality of a seed beneath the snow in the North...