"If you've done the paperwork correctly, then you can effectively enter someone onto the watch list," said Anya Bernstein, an associate professor at the SUNY Buffalo Law School and author of "The Hidden Costs of Terrorist Watch Lists," published by the Buffalo Law Review in May. "There's no indication that agencies undertake any kind of regular retrospective review to assess how good they are at predicting the conduct they're targeting."
What's more, the government refuses to confirm or deny whether someone is on the list, officially called the Terrorist Screening Database, or divulge the criteria used to make the decisions - other than to say that the database includes "individuals known or suspected to be or have been engaged in conduct constituting, in preparation for, in aid of, or related to terrorism and terrorist activities."
Even less is known about the secondary watch lists that are derived from the main one, including the no-fly list (used to prevent people from boarding aircraft), the selectee and expanded selectee lists (used to flag travelers for extra screening at airport checkpoints), the TECS database (used to vet people entering or leaving the United States), the Consular Lookout and Support System (used to screen visa applications) and the known or suspected terrorists list (used by law enforcement in routine police encounters).
For people who have landed on these lists, the terrorist designation has been difficult to challenge legally - although that may be about to change. On Monday, a lawsuit brought by a traveler seeking removal of her name from the no-fly list, or at least due process to challenge that list, is going to trial in U.S. District Court in San Francisco, after almost eight years of legal wrangling.
In that case, a Stanford University Ph.D. student named Rahinah Ibrahim was prevented from boarding a flight at San Francisco International Airport in 2005 and was handcuffed and detained by the police. Ultimately, she was allowed to fly to Malaysia, her home country, but she has been unable to return to the United States, because the State Department revoked her student visa.
According to court filings, two agents from the FBI visited Ibrahim a week before her trip and asked about her religious activities (she is Muslim), her husband and what she might know of a Southeast Asian terrorist organization. A summary of that interview obtained by Ibrahim's lawyer includes a code indicating that the visit was related to an international terrorism investigation, but it is not clear what other evidence - such as email or phone records - was part of that inquiry.
"We've tried to get discovery into whether our client has been surveilled and have been shut down on that," said Elizabeth Pipkin, a lawyer with McManis Faulkner, the firm representing Ibrahim pro bono. "They won't answer that question for us."
The government says that revealing this type of information would jeopardize national security. In April, Attorney General Eric H. Holder Jr. asserted to the court "a formal claim of the state secrets privilege" in the case.
In another case, Latif v. Holder, 13 U.S. citizens who have been denied boarding on flights are seeking removal of their names from any watch list, as well as the reasons that they have been banned and an opportunity to rebut any derogatory information.
"People who are accused of being enemy combatants at Guantánamo have the ability to challenge their detention, however imperfect that now is," said Hina Shamsi, a lawyer with the American Civil Liberties Union, which is representing the plaintiffs. "It makes no sense that people who have not actually been accused of any wrongdoing can't challenge" their inclusion on a watch list.
The Terrorist Screening Center, which administers the main terrorist watch list, declined to discuss its procedures or to release current data about the number of people on various watch lists and how many of them are U.S. citizens. A TSC official did say that fewer than 1 percent of the people in the main terrorist database were U.S. citizens or legal permanent residents, but there is no way to confirm that number.
Reports by the Government Accountability Office and other oversight agencies have raised concerns about how people are nominated to be on the terrorist watch list, the accuracy of information in the database and the effectiveness of procedures to remove or correct inaccurate records.
Travelers are entitled to file a complaint with the Homeland Security Department's Traveler Redress Inquiry Program, although that process offers limited recourse. Much information in the databases is exempt from Privacy Act disclosure requirements, so those who submit complaints often get a response saying that the government can't reveal details about their cases - one issue underlying the legal challenges now being reviewed by the courts.
Bernstein of SUNY Buffalo proposes rethinking that Privacy Act exemption, requiring regular evaluations of watch list nominations and examining the accuracy of algorithms in predicting "something as rare and idiosyncratic as terrorism."
"When you have a huge list of people who are likely to commit terrorist acts, it's easy to think that terrorism is a really big problem and we should be devoting a lot of resources to fighting it," she said. "As a society, we have choices about what we really think are the important problems."