THE Obama administration has tough words for North Korea, but it's looking to China and Russia to do the heavy lifting to punish Pyongyang for its latest nuclear test. Whether China is willing to pull away from its traditional ally is an open question given fears of raging instability that might erupt on their common border. North Korea may have overplayed its attention-getting hand – or it may be moving its nuclear brinksmanship to a higher and more opaque level. Undeterred by international criticism since the underground nuclear explosion Monday, the North has restarted its weapons-grade nuclear power plant and fired its sixth short-range missile in two days, according to news reports. The Obama administration's reaction to the nuclear test has been measured. Secretary of State Hillary Rodham Clinton, said department spokesman Ian Kelly, had been in touch with her Russian counterpart to press for “a quick, unified response to North Korea's provocative action.” Russia, once a key backer of North Korea, condemned the test. Moscow's UN ambassador, Vitaly Churkin, also the Security Council president, said the 15-member body would begin work “quickly” on a new resolution. China said it “resolutely opposed” North Korea's test and urged Pyongyang to return to talks on ending its atomic programs. While Russian objections to North Korean behavior were swift, direct and important symbolically, China holds the key. Cross-border commerce and aid from China keep North Korea afloat economically. China is North Korea's biggest source of food imports, fuel aid and diplomatic support. Many of North Korea's international connections – from air transport to financial links – are also routed through China or Chinese-controlled territories. But dramatically shaving its largesse, Beijing is believed to fear, could lead to nightmarish scenarios. One would see regime collapse and a breakdown of North Korea's million-man army, with members of the military armed with AK-47s roaming the Chinese countryside as bandits. Complicating the multidimensional chess game, key US allies in Asia – South Korea and Japan – see a fully-fledged nuclear North Korea as an existential threat, in much the same way Israel views a nuclear-armed Iran in the Middle East. Regional analogies are ofttimes wanting, but in this case it would seem to hold, given that Iran's missile program is believed to be dependent on North Korea. “There are those who say that whenever Iran conducts a missile test (as it did recently), the results benefit North Korea and vice versa,” said John Park of the US Institute of Peace. North Korea's nuclear test forced the Pentagon to scrap much of its planning for a Saturday meeting in Singapore with Defense Secretary Robert Gates and his Japanese and South Korean counterparts. “Undoubtedly, the developments in North Korea over the weekend will be a focus of that conversation,” Pentagon spokesman Geoff Morrell told reporters. Morrell said it was believed that the meeting would be the first discussion among the three nations' defense chiefs. Those who watch North Korea broadly agree that the country's latest bout of saber-rattling, which started with a long-range missile test in April, grows from an ongoing leadership transition as factions jockey for position to take power from the ailing Kim Jong Il. While Obama came to office offering to talk with the North Koreans about their nuclear program, the only answer has been belligerence – in the form of missile and nuclear tests. That would seem to make it clear that, at this point, Pyongyang does not feel the United States has anything to offer. China does and North Korea, one of the most heavily sanctioned and isolated nations on the globe, knows it. “The North must feel now that they have overplayed their hand, given the reaction of the Russians and Chinese,” said Ved Nanda, a professor at the University of Denver. But it is far from certain the Chinese will match their recent condemnation of the North with a decision to order a punishing curtailment of assistance.