U.S. Campaign Produces Few Convictions on Terrorism Charges

In addition, Taliban fighter John Walker Lindh, who is most closely associated with Afghanistan's deposed government, trained at an al Qaeda camp.

The patterns discovered by The Post are similar to findings in studies of Justice Department terrorism cases by New York University and Syracuse University, each of which examined more limited sets of data.

More than a third of the cases on the list arose from a post-Sept. 11 FBI dragnet, which resulted in the arrests of hundreds of Muslim immigrants for minor violations unrelated to the hijackings or terrorism.

"What we're seeing over time is the equivalent of mission creep: Cases that would not be terrorism cases before Sept. 11 are swept onto the terrorism docket," said Juliette Kayyem, a former Clinton administration Justice official who heads the national security program at Harvard University's John F. Kennedy School of Government. "The problem is that it's not good to cook the numbers. . . . We have no accurate assessment of whether the war on terrorism is actually working."

Tracking Al Qaeda

Before the Sept. 11 attacks, many veteran U.S. counterterrorism officials assumed that al Qaeda sleeper cells were hiding in the country, awaiting orders to launch attacks. The strikes -- carried out by 19 hijackers who arrived in the United States and trained here undetected -- prompted an aggressive campaign by the Justice Department, the FBI and other agencies to identify al Qaeda operatives on U.S. soil.

The results from the Justice Department database, however, raise the possibility that the presence of al Qaeda operatives and sympathizers within the United States is either limited or largely undetected, many terrorism experts say. "These kind of statistics show that we really don't know if they exist here in any significant way," said Martha Crenshaw of Wesleyan University in Connecticut, who has studied terrorism since the late 1960s. "It's possible that they could have sleepers planted here for a long time and we could always be very surprised. But I'd say that's less likely compared with them trying to repeat a 9/11-style infiltration from the outside."

Other experts and government officials say the relatively small number of domestic terrorism prosecutions is partly the result of the administration's strategy to handle some of its most dangerous suspects -- such as Sept. 11 mastermind Khalid Sheik Mohammed -- outside U.S. courts.

As a result, only a limited number of potentially significant cases have been pursued publicly in U.S. courts.

Viet D. Dinh, a Georgetown law professor who headed the Office of Legal Policy at Justice before and after the attacks, said the primary strategy is to use "prosecutorial discretion" to detain suspicious individuals by charging them with minor crimes.

"You're talking about a violation of law that may or may not rise to the level of what might usually be called a federal case," Dinh said, referring to credit-card fraud and other offenses. "But the calculation does not happen in isolation; you are not just talking about the crime itself, but the suspicion of terrorism. . . . That skews the calculation in favor of prosecution."

Bush administration officials have frequently compared the strategy to the anti-Mafia campaign by former attorney general Robert F. Kennedy, who vowed to prosecute mobsters for crimes as minor as spitting on a sidewalk. But many defense lawyers and civil liberties advocates argue that the Mafia analogy is misplaced.

David Z. Nevin represented Idaho graduate student Sami Omar Al-Hussayen, a Saudi national who was acquitted of federal terrorism charges in a closely watched trial last summer but agreed to be deported rather than fight immigration charges. Nevin said there are key differences between current counterterrorism cases and the prosecutions of gangsters such as Al Capone, who was famously convicted of tax evasion to get him off the street. "Everybody knew that Al Capone was committing murders and was doing all sorts of things. They just couldn't convict him," Nevin said.