During a flight to Africa two years ago, then-Secretary of State Colin L. Powell met with President Bush to discuss the crisis over North Korea's nuclear programs. A key point was that the State Department's chief negotiator at disarmament talks needed to be able to talk one on one with North Korean officials.

Powell ultimately won permission for one brief meeting, on the side of a room filled with officials from other countries. But Powell's negotiator, James A. Kelly, was permitted only to say the same thing to any question raised by the North Koreans: Go back and read my prepared statement.

But now, almost unnoted, an important shift has taken place in the Bush administration's approach to North Korea: The ban on genuine one-on-one talks has been all but abandoned.

Secretary of State Condoleezza Rice's chief negotiator, Christopher R. Hill, sealed a deal for North Korea to return to the talks during a private three-hour dinner this month in Beijing with his North Korean counterpart. Since then, Hill has held several bilateral meetings with North Korea, including a session before the talks formally began on Tuesday.

Officially, the United States maintains that nothing has changed. Officials say the meetings between Hill and the North Koreans are not negotiating sessions. Starting with Kelly's meeting in August 2003, they add, time was always found for limited discussion on the sidelines of the talks.

"This was not a negotiating session," State Department spokesman Sean McCormack said, speaking to reporters about a meeting Hill had Monday with the North Koreans. "We have in the past met with the North Koreans in the context of the six-party talks."

But, in reality, it's a significant departure for the administration, experts said.

North Korea has long insisted that it needs to discuss the nuclear issue directly with the United States. But the administration officials said they were wary of falling into the same trap as the Clinton administration, which they said negotiated an inadequate agreement freezing North Korea's nuclear programs through bilateral talks.

Now the administration appears to have concluded that progress is unlikely unless it engages directly with the North Koreans. In the talks in Beijing yesterday, North Korea formally rejected an offer made by the United States in June 2004, but the meetings Hill has held appear to have set the tone for businesslike discussions, not bluster and anger.

"Secretary Rice has implemented a subtle but important shift in U.S. policy," said Joseph Cirincione, director of nonproliferation policy at the Carnegie Endowment for International Peace. "There is no question that the lack of flexibility for the negotiators precluded any possibility of getting a deal for the past three years. Clearly, we are now in a period of give-and-take and genuine negotiations."

The evolution of the administration's approach is especially striking compared with the angst that the notion of bilateral talks generated in the first term.

"If any of this had taken placed under Bush I, people would have been lined up and shot," said Charles L. "Jack" Pritchard, the senior specialist for North Korean talks until he quit in August 2003 in protest of administration policy.

For instance, in April 2003, in a three-nation meeting that included China, Kelley was under strict instructions to have no direct meetings with the North Koreans. Pritchard, in an e-mail to colleagues, predicted: "These talks will not last the scheduled three days. The North will walk out."

After an opening session with all three parties, the North Koreans refused to attend any more meetings until they were granted a private audience. Kelly requested permission for a bilateral meeting -- and the Chinese ambassador made an appeal to Rice, then national security adviser -- but the White House refused, U.S. officials said.

Out of pique, a North Korean official pulled aside Kelly at a cocktail party and asserted that North Korea already had a nuclear weapon and might test it.

Then, when the talks moved to a six-nation format, bringing in South Korea, Japan and Russia, little was accomplished at three sessions because representatives of six nations sat at a central table and made lengthy presentations. Kelly and his team -- which included people from other U.S. agencies highly skeptical of the talks -- had to call back to Washington repeatedly for instructions.

Richard L. Armitage, then Powell's deputy, criticized the White House's approach in an interview with CNN broadcast this week: "We were looking, at least to my mind, like something out of the old Soviet days, where there were watchers watching the watchers who were watching the principals."

This week, Hill arrived in Beijing with a large U.S. delegation, but he appears to have the freedom of movement denied to Kelly. Hill speaks to Rice daily at 5:45 a.m. to update her on the talks, which would have just ended on the other side of globe.

"We sent Chris there because he's a good, tough negotiator," Rice said. "Chris knows where the principals are. He knows where our concerns are with the North Koreans. And I think everybody trusts him to get this done, if possible, within those constraints."