North Korean leader Kim Jong Il is in China. Maybe. Neither Pyongyang nor Beijing have admitted as much, though South Korean media, citing government officials, are reporting that Kim's special train passed into China overnight on Wednesday, and that the rarely traveling North Korean leader visited a middle school in Jilin province on Thursday afternoon. South Korean media and analysts speculate Kim will not visit Beijing, though he is likely to meet with Chinese officials. The timing of Kim's trip is odd for several reasons. First, Kim visited China some three months ago. Such a rapid return visit is far from the norm for the North's Dear Leader. Second, Kim left for China while former U.S. President Jimmy Carter was in Pyongyang on a mission to free a detained U.S. citizen who had crossed illegally into North Korea. It was widely anticipated that Kim and Carter would meet, and there are reports that Carter has decided to extend his visit to the North, perhaps hoping Kim would return before Carter left. Finally, the visit follows a series of unusual events surrounding North Korea, including the mysterious crash of a North Korean fighter jet in northern China, the return to government of former North Korean Premier (and erstwhile economic reformer) Pak Pong Ju, and the upcoming special meeting of the Workers' Party of Korea, where it is expected that Kim will finally announce his youngest son as his heir apparent. There is much speculation surrounding the purpose of Kim's purported trip; to gain China's support for the North Korean leadership transition (some media suggests Kim's youngest, Kim Jong Un, is along for the ride), to ask China for substantial economic aid needed in part due to recent flooding, to discuss changes in strategy for the six-party nuclear talks, to seek emergency medical care, or to discuss significant upcoming shifts in North Korean economic and foreign policies. It may be any one or a combination of these, but for Kim to make the effort to leave North Korea, particularly at a time when a former head of state of the United States is in Pyongyang appears highly significant. There is much speculation surrounding the purpose of Kim's purported trip to China. Carter's visit to Pyongyang was months in the planning, and it was not a surprise to the North Korean leadership. Kim's travels abroad normally entail weeks if not months of preparation to ensure security along whatever route he takes, and to make sure there are no potential issues that may arise in Pyongyang while Kim is out of the country. Thus, barring some very strange — and highly improbable — lack of communication in North Korea, or some tremendously important and unexpected issue, it would appear Kim either timed his trip out of the country to coincide with Carter's visit, or allowed Carter's visit in spite of Kim's brief absence. Kim's infrequent trips abroad often relate to major adjustments in North Korean economic and foreign policy, and usually include a final coordination with China or, on occasion, Russia, to ensure support from a friendly sponsor state. There have been signals from Pyongyang — directly and via China and other parties — that North Korea is preparing to return soon to multilateral talks about the North Korean nuclear program, though that shouldn't require Kim to visit China to coordinate efforts. It may be that the North is looking for assurances and cooperation should it change its stance on the sinking of the South Korean navy corvette ChonAn earlier this year. Given China's staunch support of its ally's innocence in the succeeding months, Pyongyang needs to tread carefully so as not to embarrass Beijing. Whatever the reason, it remains a fact that Jimmy Carter is in Pyongyang, apparently patiently awaiting a meeting with Kim Jong Il, although the latter has stepped out of the country for a bit. In 1994, Carter paid a visit to North Korea, much to then President Bill Clinton's chagrin at the time, and served as a conduit for North Korean founder and leader Kim Il Sung to defuse a nuclear crisis that nearly triggered U.S. airstrikes on North Korea. The Carter visit also gave Kim Il Sung the opportunity to call for a summit meeting with then South Korean President Kim Young Sam (a meeting that never took place due to the elder Kim Il Sung's death), and to shape North Korea's image abroad. While there are no immediate signs that the younger Kim is about to follow in his father's footsteps with the elder statesman Carter, even for those familiar with North Korea's often carefully choreographed "unpredictable" behavior, the current situation seems outside North Korea's pattern of behavior, and is thus notable as much for what we don't know as for what we do.