snip
Ok, apparently you're going to keep faking the relevant bits aren't there unless I copypaste them here, right? Fine.
Right after what you posted, comes this
At the same time, China has too much at stake in North Korea to halt or withdraw its support entirely. "The idea that the Chinese would turn their backs on the North Koreans is clearly wrong," says CFR Senior Fellow Adam Segal. Beijing only agreed to UN Resolution 1718 after revisions removed requirements for tough economic sanctions beyond those targeting luxury goods, and China's trade with North Korea has continued to increase. Bilateral trade between China and North Korea reached $2.79 billion in 2008, up 41.3 percent compared to 2007. Park writes that much of China's economic interactions with North Korea are not actually prohibited by the current UN sanctions regime, as Beijing characterizes them as economic development and humanitarian activities. China's enforcement of the UN sanctions is also unclear, says a January 2010 report (PDF) from the U.S. Congressional Research Service, which notes that Chinese exports of banned luxury goods averaged around $11 million per month in 2009.
Also, later:
China's support for Pyongyang ensures a friendly nation on its northeastern border, and provides a buffer zone between China and democratic South Korea, which is home to around twenty-nine thousand U.S. troops and marines. This allows China to reduce its military deployment in its northeast and "focus more directly on the issue of Taiwanese independence,"
China also gains economically from its association with North Korea; growing numbers of Chinese firms are investing in North Korea and gaining concessions like preferable trading terms and port operations. Chinese companies have made major investments aimed at developing mineral resources in North Korea's northern region.
Experts say China has also been ambiguous on the question of its commitment to intervene for the defense of North Korea in case of military conflict. The 1961 Sino-North Korean Treaty of Friendship, Cooperation, and Mutual Assistance says China is obliged to defend North Korea against unprovoked aggression. But Jaewoo Choo, assistant professor of Chinese foreign policy at Kyung Hee University in South Korea, writes in Asian Survey that "China conceives itself to have the right to make an authoritative interpretation of the principle for intervention" (PDF) in the treaty. As a result of changes in regional security in a post-Cold War world, he writes, "China now places more value on national interest, over alliances blinded by ideology." But, he argues, Chinese ambiguity deters others from taking military action against Pyongyang.
even though China may be angry at North Korea's nuclear brinkmanship, analysts say it will avoid moves that could cause a sudden collapse of the regime. Given the competition for influence in preparation for the eventual passing of a physically weak Kim Jong-Il, China may feel even more restrained from pressuring North Korea for fear of alienating a future power base.
To be fair, they do post a (somewhat) dissenting opinion in the end:
But Asian military affairs expert Andrew Scobell writes, "No action by China should be ruled out where North Korea is concerned." According to Scobell, Beijing might stop propping up Pyongyang and allow North Korea to fail if it believed a unified Korea under Seoul would be more favorably disposed toward Beijing. A January 2008 report by the Center for Strategic and International Studies and the U.S. Institute of Peace, two Washington-based think tanks, says China has its own contingency plans (PDF) to dispatch troops to North Korea in case of instability. According to the report, the Chinese army could be sent into North Korea on missions to keep order if unrest triggers broader violence, including attacks on nuclear facilities in the North or South.
but the outline and analysis of the article is pretty clear.