New York University's Center on Law and Security released a terror trial "report card" covering the years 2001 to 2009 that claims there have been 337 federal terror cases, though each case can involve multiple defendants charged with multiple crimes. In March 2010, in response to questions from Congress about the numbers, the Justice Department released its own report that listed 403 individuals convicted of terror-related charges in 37 different states (including the District of Columbia.) In December 2011, the group Human Rights First cited new DOJ figures to that put that updated number at 494, including 67 cases where the suspect was arrested outside the United States. This Associated Press report from 2011 says the number of convictions in the U.S. is more than 2,500, though they are obviously using a much broader definition of "terror" than the feds do.
There have been numerous objections to the official number over the years, but even the most conservative definition of the term "terrorism" pegs the number of convicted individuals somewhere between 150 and 220, including "20th hijacker" Zacarias Moussaoui (pictured above). The number of people convicted by military tribunal since 2001? Seven.
Even though Guantanamo Bay, Cuba, has held nearly 800 prisoners since being established 11 years ago, only seven individuals held there have ever been tried and convicted by a military commission. Only three are still in jail. Two of those were overturned and three more have already been released and deported to other countries. Six others, including Khalid Sheik Mohammed, who was captured more than 10 years ago, still await their tribunals. Yet, the Justice Department claims to have over 300 prisoners currently serving sentences in regular U.S. prisons, with no deaths or escapes. Meanwhile, there are 166 prisoners currently at Guantanamo—and half are actively trying to kill themselves.
Even more remarkable is that the NYU Law School study says the conviction success rate on terror cases in civilian courts is nearly 90 percent. That includes plea bargains, but it shows how remarkably easy it is to put someone in jail (too easy, perhaps) when the case involves the threat of a terror attack. It helps that civilian courts offer a wider range of possible charges, but the limitations placed on military commissions (no immigration or drug cases) is just another reason to avoid using them when possible.
If the goal is to make sure Dzhokhar Tsarnaev spends the rest of his life in prison, it's hard to argue that a civilian court is not the way go. They work faster, they close cases better, and they're less likely to let people go home early. (The second charge against Tsarnaev, use of a weapon of mass destruction, could lead to capital punishment if prosecutors push for it at a later date.)