LONDON -- As it struggles to combat Islamic terrorist networks, the Bush administration quietly has built an intelligence alliance with Moammar Khadafy, leader of Libya and a onetime bitter enemy the United States had tried for years to isolate, topple, or kill.
Khadafy has helped the United States pursue Al Qaeda's North African network by turning radicals over to neighboring pro-Western regimes. He also has provided information to the CIA on Libyan nationals with alleged ties to international terrorism.
In turn, the United States has handed over to Tripoli some anti-Khadafy Libyans captured in its campaign against terrorism. And Khadafy's agents have been allowed into the Guantanamo Bay detention camp in Cuba to interrogate Libyans held there.
The rapprochement is partially the result of a decade of efforts by Khadafy to improve relations with the United States and end international sanctions imposed on Libya for bombing Pan Am Flight 103 over Lockerbie, Scotland, in 1988. But it also reflects the fact that Libya and the United States regard Islamic extremism as a common enemy. Even though he long supported radical causes, Khadafy views religious militants as a menace to his secular regime.
''Their assistance has been genuine, if motivated in large measure by self-preservation," Bruce Hoffman, director of counterterrorism and counterinsurgency studies at Rand Corp., said of the Libyans. ''You have to give Khadafy credit for recognizing the existential threat posed to his rule and revolution by [Osama] bin Laden and Al Qaeda."
Critics allege that the partnership with Libya, like those with regimes such as Sudan, Uzbekistan, and Egypt, shows how Washington is allowing its war on terrorism to trump its effort to promote democracy and human rights in the Muslim world. They say that in cooperating with Khadafy, the United States has strengthened his regime and permitted him to crack down on political foes, some with far stronger democratic credentials than his own.
Khadafy's point man for dealing with Washington, head of foreign intelligence Musa Kusa, is banned from entering the United States because of his suspected involvement in terrorist acts, including the Lockerbie bombing. He also is suspected of taking part in a plot to kill Saudi Arabia's ruler.
Libyan dissidents, who for years thought they could count on US support, have been disappointed by the Bush administration. ''Khadafy was considered to be a dictator and terrorist, and Libya was a rogue regime," said Ashur Shamis, a London-based Libyan exile and longtime proponent of democratic reform. ''Suddenly, everything has changed.
''The Americans no longer want to see Khadafy's regime destabilized," he said. ''Opponents have written off the possibility of receiving tangible political support from the United States."
Libya's decision in 1999 to turn over suspects in the Pan Am bombing, which killed 270 people, and, 4 1/2 years later, its renunciation of developing nuclear weapons have been the most public examples of its effort to improve relations. But specialists say Khadafy had been moving in that direction because sanctions had crippled the economy and generated high unemployment, shortages of goods, and political discontent.
Khadafy came to power in 1969 at 27, when he led a coup that overthrew Libya's pro-Western monarchy. A decade later, the Carter administration placed Libya on a list of state sponsors of terrorism, where it remains. In April 1986, US warplanes attacked Libya in retaliation for the bombing of a Berlin disco that killed three people, including two US soldiers. The US attack killed more than 60 people, including Khadafy's 15-month-old daughter.
Meanwhile, the CIA funneled millions of dollars in money and equipment to anti-Khadafy rebels.
Khadafy began reaching out to the United States as early as the mid-1990s, expelling or severing ties with radical groups. In April 1999, he surrendered two Libyans suspected in the Pan Am bombing. The Clinton administration responded by launching secret talks with Tripoli, the Libyan capital.
The thaw accelerated in January 2001 with the inauguration of President Bush and the conviction of Abdel Basset Ali Megrahi of murder in the Lockerbie case. A Scottish court said Megrahi had acted ''in furtherance of the purposes of . . . Libyan Intelligence Services," but it acquitted a second man. In 2003, Libya agreed to a $2.7 billion payout to families of the Lockerbie victims. American oil companies, anxious to invest in Libya, heavily lobbied the Bush administration to improve ties.
Relations improved markedly after the Sept. 11, 2001, attacks, which Khadafy immediately condemned. He said the United States had the right to retaliate, and urged Libyans to donate blood for American victims. He subsequently said Libya and the United States had a common interest in fighting Islamic extremism.
The intelligence partnership between the United States and Libya has unfolded mostly in private, but both sides publicly have acknowledged its existence. In an accord reached this year, the CIA agreed to offer counterterrorism training to Libyan security personnel, two US government sources familiar with the deal said.
A senior US official, who spoke on the condition of anonymity, said Libya's counterterrorism cooperation was important to the United States and compared it to ''the relationship we have with our longstanding friends." The official acknowledged that Kusa might have been involved in acts of terrorism in the past, but said he was not under indictment in the United States and had been helpful. ''This is a regime that has had its hands dirty in the past; we have to be careful about how to deal with them. The most important thing is to make sure they don't do it again," the official said.