China's policy on North Korea unlikely to change with additional nuke tests

China is unlikely to fundamentally shift its policy toward North Korea as a buffer state against South Korea and the United States "even with a fourth nuclear test," two security experts said Tuesday. In February North Korea conducted its third and most powerful nuclear test since 2006, drawing international criticism and tightened sanctions, even from its major ally China. Although there is no immediate sign of another nuclear test, South Korean officials said the North is ready to carry out the fourth test at any time. "China's security calculus vis-a-vis North Korea rests largely on the belief that it retains significant value as a buffer state," according to a joint report by Zhu Feng, a professor of Peking University, and Nathan Beauchamp-Mustafaga of the International Institute for Strategic Studies. The report was presented at a conference of the Council for Security Cooperation in the Asia Pacific that took place in Beijing. 'While China incurs substantial indirect security costs for its relationship with the North, leaders in China still see tangible and intangible benefits that evidently outweigh these costs," the report said. "It seems unlikely that this calculus will change in the near future, even with a fourth nuclear test, and thus China's policy towards the North will likely experience little change as well," it said. Diplomatic efforts to resume the long-stalled talks on North Korea's nuclear program appear to have been failing to gain traction, as the North has rejected preconditions set by South Korea and the United States to reconvene the six-party talks. The talks, which involved the two Koreas, the U.S., China, Russia and Japan, have been dormant since late 2008. Since conducting its third nuclear test earlier this year, North Korea has repeatedly expressed its willingness to reopen the six-party process "without preconditions."    South Korea and the U.S. have been demanding North Korea show its sincerity first by taking steps to denuclearize itself. China has been more accommodating toward North Korea, urging South Korea and the U.S. to lower their bar for Pyongyang to sit down at the negotiating table.