The legacy of the late North Korean leader Kim Il Sung's decision in the early 1990s to pursue a strategic partnership with the United States has run its course. In its place, the focus of Pyongyang's policies has decisively shifted to Beijing. However wary the North Koreans may be of their neighbor, the fact is that from Pyongyang's viewpoint, the Chinese have delivered and the United States did not.

Any shards remaining from the North's previous, decades-long effort to normalize ties with the U.S. were swept away by current leader Kim Jong Il's trip in May to China, his third in barely a year. Based on our discussions with Chinese officials, we believe that during that visit, Pyongyang and Beijing came to an understanding that, in preparation for planned, major domestic political events in 2012, both sides require sustained political stability, a convergence of interests that provides the opportunity for expanding bilateral relations beyond anything enjoyed in the past. The North is building toward a "prosperous and powerful" nation in celebration of the Kim Il Sung centenary in April; the Chinese are looking toward their 18th Party Congress scheduled for late next year. In both cases, it was apparently decided, stability on the Korean peninsula would serve economic programs and the succession of a new generation of leaders.

In the arrangements — formal and informal — that emerged from Kim Jong Il's discussions with his hosts, Pyongyang agreed not to "make trouble" (as the Chinese described it to us) in the short term, presumably meaning no deliberate military provocations, no third nuclear test and no launch of another ballistic missile. Beyond that, the talks ended in a compromise that neither side found entirely satisfactory. Kim came away with less aid and a smaller Chinese commitment of support than he had sought, though Pyongyang typically asks for more than it can get.

The North did, however, receive increased access to both Chinese capital and technology in spite ofUnited Nations and other foreign sanctions. Kim also obtained, through the establishment of joint economic zones with China along the Yalu River, a locale to test adjustments necessary to economic development, adjustments that would fall short of what Beijing considers genuine economic reform. Chinese President Hu Jintao, we were told, had to settle for Kim's promise to cause less trouble but without a North Korean commitment to serious steps toward denuclearization.

We believe that this pivot toward Beijing is no routine oscillation in North Korean policy. The drive to normalize relations with the U.S. from 1991 to 2009 had been real, sustained and rooted in Kim Il Sung's deep concern about the regime's future in the aftermath of the collapse of the Soviet Union. Perhaps there was no better demonstration of the North's approach in those years than the situation on Oct. 25, 2000 — the 50th anniversary of the entry of the Chinese People's Volunteers into theKorean War. Who was in Pyongyang on that date meeting Kim Jong Il? The Chinese defense minister? No, he was cooling his heels while Kim met with the U.S. secretary of State. That was no accident of scheduling on Pyongyang's part; it would not happen again today.

If the paradigm shift is real, we expect the North in the near to medium term to make far less overt trouble. Less tension on the Korean peninsula? What could be wrong with that? Nothing, as long as it is understood that such tranquillity will also provide a veil for the North's continuing pursuit of nuclear weapons and increasingly sophisticated delivery systems. With the onset of stability and growing Chinese-North Korean cooperation, Pyongyang may well calculate that the outside world's focus on the North Korean nuclear program will become diffuse. Indeed, the North Koreans have long assumed that given enough time, the world would resign itself to their nuclear weapons, as happened with India and Pakistan.

To help things along, it isn't out of the question that Pyongyang might even agree to some U.S. efforts to contain the nuclear program through a series of what Washington calls "pre-steps." The North has repeatedly expressed willingness to consider discussion of its uranium enrichment program and moratoriums on missile and nuclear tests. As unilateral actions, these would have short-term benefits by further stabilizing the situation to provide additional room for discussions. But in the absence of long, serious negotiations between the two sides, they will turn out to be no more meaningful than the ill-considered agreements of the now moribund six-party talks.

All of which brings us back to the deepening North Korean-Chinese ties, and the downgrading in Pyongyang's calculations of relations with the United States. There was considerable momentum behind the North's strategy for engaging the U.S. in past negotiations. That is no longer the case, with consequences we have only started to feel.

The United States gives Pakistan billions of dollars in aid each year. Pakistan returns the favor by harboring terrorists, spreading anti-Americanism, and selling nuclear technology abroad. The bribes and the begging aren’t working: only threats and the determination to act on them will do the job. Washington must tell Islamabad to start cooperating or lose its aid and face outright isolation.