I have some thoughts about this decision.
1. It is my belief that this is the best way to defeat the terrorists. Al-Qaeda sees itself at war with the West and they want to west to react militarily so that the West overreacts and muslims respond by joining Al-Qaeda. Why would we want to play by the rules? I think treating Al-Qaeda like criminals will defuse the myth that they are super villains and deflate their standing.
It is my firm belief that the best way t defeat them is to use the institutions that enshrine the values of our democracy. Our ideals and values are stronger and more enduring than any bomb. Demonstrating our values in action before the world(friend, enemy, and skeptical) will do more to come closer to victory then any military action.
2. I do not understand the objections to the Attorney General's decision. I no see no security threat. Our courts and police have handled plenty of terrorists and other dangerous criminals. The Federal courts have successfully prosecuted the first world trader center bombers(in New York City), Eric Robert Rudolph, the Oklahoma City Bombers, and 20th hijacker Zacarias Moussaoui. All of these trials went off safely and without any security disruption.
As for the fear of terrorists being released on a technicality; I think that fear is is misplaced. A "technicality" usually means the police or the prosecutor were sloppy. On a case as important as one involving Al-Qaeda, we would want our police and prosecutors to give their best and most detailed effort.
I also don't buy the threat of losing an intelligence resource. If there are safety considerations about an informant then our government contains plenty of people with expertise in providing security to witnesses. Otherwise the chance to public bring Al-Qaeda terrorists to justice and hold them to account in front of the whole world is worth the risk to our intelligence resources.
The U.S. effort against Al-Qaeda has suffered from too many self inflicted wounds. It is time that the U.S. anti-terrorism efforts earn a victory by upholding U.S. values and the institutions that uphold those values. Attorney General Holder's decision is a good first start.