Washington. North Korea’s latest outburst of nuclear and military threats has given the U.S. a rare opportunity to build bridges with China—a potential silver lining to the simmering crisis that could revitalise the Obama administration’s flagging policy pivot to Asia.The architect of the administration’s Asia policy described a subtle change in Chinese thinking as a result of Pyongyang’s recent nuclear tests, rocket launches and abandonment of the armistice that ended the 1950-53 war with South Korea.Pyongyang has taken similar actions in the past, prompting Washington to step up military readiness in the region to soothe allies South Korea and Japan. But in an unusual rebuke this week, Beijing called North Korea’s moves "regrettable”—amounting to a slap from Pyongyang’s strongest economic and diplomatic supporter."They, I think, recognise that the actions that North Korea has taken in recent months and years are in fact antithetical to their own national security interests,” former Assistant Secretary of State Kurt Campbell told a panel Thursday at the Johns Hopkins School of Advanced International Studies."There is a subtle shift in Chinese foreign policy toward North Korea,” said Campbell, who retired in February as a top diplomat in East Asia and the Pacific region. "I think Pyongyang has succeeded in undermining trust and confidence in Beijing.”State Department spokeswoman Victoria Nuland described "good unity” between the US and China in responding to North Korea."The issue here is to continue to recognise that the threats we share are common, and the approaches are more likely to be more effective if we can work well together,” she told reporters Thursday.North Korea’s threats have focused China and the US on a regional security threat instead of an economic rivalry.North Korea has ratcheted up an almost daily string of threats toward the US, South Korea and Japan and moved a missile with "considerable range” to its east coast.