As I'm guessing the little "Edit" here is for....

....what most people do not realize is that it costs far more to put someone to death than for them to spend life in prison. Court costs are much higher than is the cost of bread & water and a 8x8 jail cell.

You can be pretty certain that Moussaoui will not appeal his guilty verdict in this case, so as far as the courts go, this case is closed. But if he had been sentenced to death, most likely there would have been an appeals process. That means hearings in front of a judge, with court employees, state-provided legal team, etc. One day in court costs more than 10 years in prison. Now multiply that by however many appeals you are allowed, and you can see how it is so expensive.

Also, the appeals process takes time. If you ever watch the news, whenever they execute someone, it is usually for a crime that took place 20 years ago. That's beause with the backlog of cases in our courts, it takes that long to get through all the appeals. So you are still paying for 20 years in prison.

In this case especially, giving him the death penalty accomplishes nothing but "revenge". It will not scare future terrorists into submission.

I say it does not really matter one way or the other, and just let him rot in jail because that is the easier and less expensive thing to do. Our legal system is cluttered enough with nonsense. Just move on to the next case and be done with this one.