It's unlikely that we will ever know how many people were wrongly and summarily imprisoned, tortured, or otherwise abused in the aftermath of 9/11, but we do know that illegalities were systemic. A report by the Justice Department's inspector general released back in 2003 documented the abusive, extended detention of immigrants (often on minor charges) in the months following 9/11. Since then, the release of Central Intelligence Agency documents reviewing "interrogation activities" between 2001 and 2003, as well as Justice Department memoranda describing in chilling bureaucratic detail permissible "enhanced interrogation techniques," have made clear that torture was an official strategy, not an occasional excess.
"Aggressive detention of lawbreakers and material witnesses" was also official strategy, announced by then-Attorney General John Ashcroft at a 2001 press conference. It's hard to argue with "aggressive detention of lawbreakers" or even actual material witnesses, in theory. But, in practice, this policy apparently involved preventative detention and the wrongful use of a material-witness statute to arrest people without legal cause.
A September 4, 2009, decision by the Ninth U.S. Circuit Court of Appeals may shed more light on unlawful "material witness" detentions. In Al-Kidd v. Ashcroft, a three-judge panel ruled that John Ashcroft could be held liable for the unconstitutional arrest of Abdullah al-Kidd as a material witness. (The Court did not rule on the merits of al-Kidd's constitutional claim. Al-Kidd v. Ashcroft was a procedural ruling that rejected Ashcroft's claims of immunity and allowed the lawsuit against him to go forward.)
Abdullah al-Kidd is an American citizen who converted to Islam. He was arrested under a material-witness statute in March 2003 at Dulles International Airport, detained in high-security cells for a little over two weeks, and subjected to multiple strip searches. After his release from custody on court order, he was placed on strictly supervised probation for some fifteen months. He was never charged with a crime or called to appear as a material witness, but by the time he was freed, his marriage had broken up, and he'd lost his job.
The case that ostensibly justified al-Kidd's arrest as a material witness was quite weak. The government had arrested a graduate student in computer science, Sami al-Hussayen, who had volunteered as a webmaster for a legal Islamic charity. Initially arrested and imprisoned on minor immigration charges and for making false statements on his immigration form, al-Hussayen was eventually indicted on terrorism charges and acquitted after a jury trial in federal district court in Idaho.
In other words, the government arrested and imprisoned one man (al-Hussayen) on highly questionable charges that it could not prove (charges based on activity protected under the First Amendment) and then arrested and detained another man (al-Kidd) on the pretext that his testimony was required in the case against the first man. Moreover, as the Ninth Circuit observed, al-Kidd's arrest warrant was partly based on misrepresentations and omissions of fact: Federal agents claimed that he was about to fly to Saudi Arabia on a one-way first-class ticket; in fact, he had a round-trip coach ticket. Additionally, agents neglected to mention that al-Kidd was an American citizen--as were his parents, his wife, and two children--and that he had previously cooperated with the FBI when its agents wanted to interview him.
Somehow I doubt that al-Kidd's apparently illegal arrest and detention helped keep us safe. The 9th Circuit found the government's conduct "repugnant," and expressed confidence that the Framers would have "disapproved of the arrest, detention, and harsh confinement of a United States citizen as a 'material witness'" in this case. (Tea Partiers should take note.) Yet, as the Court observed, when FBI Director Robert Mueller testified before Congress in March 2003, he cited al-Kidd's arrest as one of five "major successes" in "identifying and dismantling terrorist networks." I wonder what Mueller would consider a failure.