A top U.S. diplomat was on his way to North Korea on Tuesday to try to stop the unraveling of a nuclear agreement.
Earlier this year, North Korea completed steps to disable its primary nuclear facility. In exchange, the United States was supposed to lift some sanctions and remove North Korea from the list of states that sponsor terrorism.
The U.S. has failed to do that, and now North Korea has moved to reconstitute its nuclear infrastructure.
At its nuclear facility at Yongbyon, North Korea removed seals and video cameras installed by the International Atomic Energy Agency (IAEA) to make sure the facility was not reprocessing spent nuclear fuel into plutonium. It told inspectors from the IAEA to leave.
Just a few days ago, the agency's spokeswoman, Melissa Fleming, indicated that more unpleasant news was on its way.
"The DPRK has also informed the IAEA inspectors that they plan to introduce nuclear material to the reprocessing plant in one week's time," she said, referring to North Korea by its formal name, the Democratic People's Republic of Korea, or DPRK.
The reprocessing facility was shut down and disabled earlier this year, as was the whole complex at Yongbyon, whose cooling tower was dynamited for all to see in June.
President Bush said at the time that he would ask Congress to remove North Korea from the list of state sponsors of terrorism, but that hasn't happened, prompting North Korea's actions last week, said Evans Revere, president of the New York-based Korea Society.
"They feel that somehow they have been misled or led astray in the negotiations, and they have been stating publicly that they feel that they were promised things that were not delivered upon," Revere said.
The United States has complaints as well, focused on the issue of verification. It says North Korea was supposed to agree to a whole set of verification measures to make sure it was telling the truth about the details of its nuclear program.
A few days ago, the U.S. proposals for verification measures were made public. They permit American and international inspectors to go virtually anywhere in the country that they believe might be linked to the North Korean nuclear program.
North Korea said no, and that may be what some in the Bush administration wanted. There are still hard-liners who oppose the deal with North Korea, and they may have stacked the verification proposal with provisions they knew Pyongyang would not accept.
Assistant Secretary of State Christopher Hill, the chief U.S. negotiator with North Korea, acknowledged that the verification issue had become a big hurdle.
"It's a tough process. It's not about what you write on a piece of paper. It's about what you do on the ground," Hill said. "It's about, you know, going into nuclear facilities in a way we haven't done before. It involves proving out figures involving the amount of fissile material they have, so we're in a degree of detail we haven't had before."
Hill is the diplomat who was on his way to Pyongyang on Tuesday to see whether he can salvage the deal.
The problems may be somewhat of his own making. Some experts say Hill negotiated a deliberately vague agreement with North Korea, which may have left both sides unable to carry the deal out fully.
"There's enough ambiguity in the understandings and arrangements here to justify some of the things that each side has been saying here," Revere said.
There is also one other big problem — the health of North Korea's leader, Kim Jong Il. Recent reports suggest he may have had a stroke, and he has not been seen in public for months.
Hill acknowledged that might account for North Korea's hardening stance.
"How decisions are made in North Korea is always a bit of an opaque process, and certainly this month has been no exception to that," Hill said. "But clearly we are seeing a tough line in the last month from them."
It may be that the nuclear deal with North Korea will not move forward until the uncertainty about the leadership in North Korea and the United States gets sorted out.
In the meantime, experts say it will take weeks for the North Koreans to begin producing plutonium, despite their claims that they would start this week. U.S. officials remain at Yongbyon to monitor the activities there.