It took months for Washington to clear obstacles preventing the money’s return, a move that hawks in the administration had argued was deeply mistaken.

Now Mr. Hill can pursue the next items on his agenda: Persuading North Korea to fulfill a commitment it made in February to slow down its main nuclear reactor, whose spent fuel has enabled the country to manufacture plutonium and gain the fuel for eight or more nuclear weapons, according to public American intelligence estimates.

In the next step, the North is supposed to provide the United States and the other participants in the six-party negotiations on the issue — Japan, South Korea, Russia and China — with a detailed list of all of its nuclear programs and facilities.

The Bush administration is also considering authorizing Mr. Hill to offer to buy from the North Koreans nuclear equipment that they are believed to have purchased several years ago from Abdul Qadeer Khan, the Pakistani nuclear engineer. That equipment could conceivably give the North a second path to building a bomb, by enriching uranium.

But American officials do not know whether the North ever learned the secrets of enrichment, or where enrichment facilities might be. So far, the North has denied that it possesses the equipment.

“This is critical to the administration’s plan,” one senior official involved in the North Korea strategy said, “because unless they get their hands on this stuff, there is no way we can argue that we’ve stopped the North from making more nukes.”

But it was unclear whether Mr. Hill was prepared to make the offer to the North now, or what form it would take. While Washington or its allies could offer cash for the equipment, they might also promise future deliveries of nuclear fuel to power the civilian nuclear reactors the North insists it needs.