North Korea diplomatic channel loses its luster But the importance of the New York channel has been noticeably diminished over the years, according to diplomats. Today, with the United States and North Korea at a standoff and the threat of a fourth nuclear test by the North looming, Han's channel has been reduced to a diplomatic P.O. box that passes occasional messages between capitals and arranges travel for VIP visits to Pyongyang. The shift, diplomats and others say, underscores the radicalization of North Korea's foreign policy and a growing pessimism that relations can be improved. "These people in New York are not authorized to say anything or do anything - they don't have the authority to deviate from specific instructions," said Han Park, a professor at the University of Georgia with long-standing ties to the North Korean government. The diminished status of the New York channel also speaks to the waning influence of the North Korean Foreign Ministry, which oversees the conduit, in shaping the country's relationship with the United States. For its part, the Obama administration has shown little interest in cultivating the channel more assiduously, on the grounds that Han Song Ryol and his colleagues have little influence back home and little authority to advance relations, according to diplomats and former U.S. officials. In the absence of a more substantive diplomatic channel, tensions between North Korea and the United States have mounted in recent weeks, with Pyongyang issuing a series of increasingly provocative threats. To persuade North Korea to change course, the United States has relied on economic pressure, including a new round of U.N. sanctions, and hopes that China can use its leverage to convince Pyongyang that it should stand down. Some North Korea watchers say the New York channel remains important, particularly at a time when the North, which recently severed its few lines of communication with the South, has moved to further isolate itself. "It serves only as a communications channel, although messages can be and have been sent between the highest levels of the two governments," said Kun A. "Tony" Namkung, who maintains close contacts with the mission and who helped arrange recent visits to Pyongyang by former New Mexico governor Bill Richardson and Google chief executive Eric Schmidt. It remains wide open and is in good shape. Given the recent cutting off of the military hotline at the DMZ, its importance has actually increased," he added, referring to the demilitarized zone between the two Koreas.