A fresh effort to resume nuclear-weapons talks with North Korea looks promising – except for one serious obstacle. Officials in Pyongyang have told a U.S. congressional delegation that North Korea is ready to resume negotiations if the reorganized Bush administration doesn’t go on with its slanders and interference in North Korea’s internal affairs.

The North Koreans may be pleased by the departure of the State Department’s top international security and arms control officer, Under Secretary John Bolton. Mr. Bolton has been a hard-line opponent of any concessions to North Korea. He has denounced the Pyongyang regime as a tyrannical dictatorship, and North Korean officials have called him a “scum” and refused to meet with him. News that he is leaving has led some observers to suggest that the new secretary of state-designate, Condoleezza Rice, may be seeking a diplomatic solution.

Standing in the way of this somewhat optimistic prospect is a long-standing administration charge that North Korea is operating a program to use uranium to make nuclear weapons. The accusation was made in the North Korean capital on Oct. 4, 2002, by James Kelly, assistant secretary of state for East Asian and Pacific affairs, and pressed ever since by Mr. Bolton and President Bush. The problem is that the charge is based on secret CIA evidence that is widely doubted.

Mr. Kelly said at the time that a senior North Korean official had acknowledged the existence of the alleged uranium-enrichment program. But the official, First Deputy Foreign Minister Kang Sok Ju, has since denied this. He has maintained that what he actually said was that North Korea was “entitled” to have such a program to deter a preemptive U.S. attack. (North Korea, like the United States, always refuses to confirm or deny any specifics about its nuclear capabilities.)

A leading American specialist in North Korean affairs, Selig S. Harrison, tells the whole story in the new issue of the respected journal Foreign Affairs, published by the Council on Foreign Relations. Mr. Harrison writes that the charge would be more persuasive if the CIA had made a credible case to congressional committees in executive session or to U.S. Asian allies. He checked with officials of South Korea, Japan, China and Russia, the other parties to the stalled negotiations, and learned that none of them had received supporting evidence.

The mystery over the alleged uranium enrichment program is important because it would be a violation of the 1994 freeze on North Korea’s nuclear weapons program negotiated by the Clinton administration. The Bush administration declared that North Korea’s cheating meant that the United States was no longer bound by the deal. It halted oil shipments that were part of the agreement. North Korea retaliated by expelling international inspectors and resuming its reprocessing of plutonium, one method of making nuclear weapons material. The Bush administration has been demanding that North Korea admit publicly that it also has a uranium enrichment program before the talks can resume.

So the far more dangerous and well-known plutonium program goes forward, free of international inspection, while the less urgent question of a uranium enrichment program blocks further talks.

An obvious course is to seek step-by-step concessions including inspections and a new freeze, but the rhetoric will have to cool down first. The obstacle is persuading the leaders in either capital to be willing to put safety ahead of perceived threats.