General Musharraf, in his memoir, “In the Line of Fire,” published last year, did not discuss any equipment, training or technology offered then, but wrote: “We were put under immense pressure by the United States regarding our nuclear and missile arsenal. The Americans’ concerns were based on two grounds. First, at this time they were not very sure of my job security, and they dreaded the possibility that an extremist successor government might get its hands on our strategic nuclear arsenal. Second, they doubted our ability to safeguard our assets.”

General Musharraf was more specific in an interview two years ago for a Times documentary, “Nuclear Jihad: Can Terrorists Get the Bomb?” Asked about the equipment and training provided by Washington, he said, “Frankly, I really don’t know the details.” But he added: “This is an extremely sensitive matter in Pakistan. We don’t allow any foreign intrusion in our facilities. But, at the same time, we guarantee that the custodial arrangements that we brought about and implemented are already the best in the world.”

Now that concern about General Musharraf’s ability to remain in power has been rekindled, so has the debate inside and outside the Bush administration about how much the program accomplished, and what it left unaccomplished. A second phase of the program, which would provide more equipment, helicopters and safety devices, is already being discussed in the administration, but its dimensions have not been determined.

Harold M. Agnew, a former director of the Los Alamos weapons laboratory, which designed most of the United States’ nuclear arms, argued that recent federal reluctance to share warhead security technology was making the world more dangerous.

“Lawyers say it’s classified,” Dr. Agnew said in an interview. “That’s nonsense. We should share this technology. Anybody who joins the club should be helped to get this.”

“Whether it’s India or Pakistan or China or Iran,” he added, “the most important thing is that you want to make sure there is no unauthorized use. You want to make sure that the guys who have their hands on the weapons can’t use them without proper authorization.”

In the past, officials say, the United States has shared ideas — but not technologies — about how to make the safeguards that lie at the heart of American weapons security. The system hinges on what is essentially a switch in the firing circuit that requires the would-be user to enter a numeric code that starts a timer for the weapon’s arming and detonation.