Since Attorney General Eric Holder decided to try Khalid Sheikh Mohammed, the professed mastermind of the Sept. 11, 2001, attacks, in civilian court, Republicans have argued that a military trial would be a better solution. Administration officials respond by saying hundreds of terrorists have been convicted in federal court. But there is widespread disagreement on the specific number of terrorism convictions since the attacks.
In an interview Sunday on CBS, President Obama said the Bush administration "prosecuted 190 folks in these Article 3 courts and got convictions."
His number matches a report that the group Human Rights First issued in July. "We specifically looked at self-described Islamic or jihadist terrorists," says Human Rights First Senior Associate Daphne Eviatar. "So these are people who are generally linked in some way to al-Qaida or the Taliban."
The federal government's list of terrorist groups includes some organizations with no Islamic ties, such as the Tamil Tigers in Sri Lanka and the FARC in Colombia. When one includes those cases, the tally of terrorism convictions goes up.
Whose Numbers Are They, Anyway?
In testimony before the Senate Judiciary Committee in November, Holder said, "There are more than 300 convicted international and domestic terrorists currently in Bureau of Prisons custody."
Republicans have attacked that number as inaccurate. Jeff Sessions (R-AL), the ranking member on the Senate Judiciary Committee, called the 300 figure "unsubstantiated." President Bush's former press secretary, Dana Perino, said the statistic is as "false as false gets." But the number actually comes from a Bush administration document. In 2008, the Justice Department submitted a budget request citing "319 convictions or guilty pleas in terrorism or terrorism-related cases arising from investigations conducted primarily after September 11, 2001."
The NYU Center on Law and Security conducted its own comprehensive study and came up with yet a higher number.
"If you had every single terrorism-related prosecution since 9/11 and you wanted to know the convictions, there would be 523," says the center's director, Karen Greenberg.
Her database includes everything from the smallest terrorism-related passport violation to the case against Sept. 11 plotter Zacarias Moussaoui. "The point," Greenberg says, "is to have a database that has everything in it so that you can crunch for all of the different things, and that's what we do."
Many tallies of terrorism convictions include cases the government labeled as "terrorism related" at the time of arrest, where the connection to terrorism was tenuous at best.
"Right after 9/11, the government was classifying people who in no way were terrorists," says David Burnham, co-director of Syracuse University's Transactional Records Access Clearinghouse. "A woman was on an airline, and she kept hitting her call button. She surely terrorized the flight attendants, but she was not a terrorist. And she got arrested and was classified as a terrorist."
Those sorts of cases have become less common in recent years, according to NYU's study. The report says that as the government has refined its approach to terrorism, prosecutors have brought fewer cases. The crimes have tended to be more serious, and conviction rates have gone up.
Still, says Burnham, any study of terrorism convictions inevitably relies on subjective decisions about which cases to include and which to omit. "Depending on how you count," he says, "you get different answers."