A former CIA official has spoken to UPI:
"At the heart of the issue is a remarkable legal document, known as a Memorandum of Notification, which was signed by President Bush less than a week after the Sept. 11 attacks.
In the effort to justify the broad legal authority it granted the United States to kill its terrorist enemies, some administration lawyers drew on a legal theory of anticipatory self-defense, first developed as a strategy for battered women who had killed their abusers...
The former official said the anticipatory self-defense theory enabled the administration to get around the long-standing ban on U.S. personnel taking part in or procuring assassinations stipulated in Executive Order 12333. Self-defense is not a defense for the crime of homicide. If a killing is self-defense, no crime has been committed."
Richard Clarke told a congressional inquiry "There was concern ... that we not create an American hit list that would become an ongoing institution that we could just keep adding names to and have hit teams go out and assassinate people." but the former CIA official said interference from the lawyers:
"It got so ridiculous. When we were training for an operation to capture bin Laden, the lawyers made us build an ergonomic chair in which he would be comfortable. ... At one point we took three rolls of tape to the lawyers (at the National Security Council) -- duct tape ... masking tape and white adhesive tape -- so they could decide which we could use to put over his mouth that would be least uncomfortable."
I've no idea how much if any of this is real but it gives an insight into how nasty and difficult the actual business of managing the fighting of terrorism can be. You can understand the anger of intelligence operatives who have to put their lives on the line but if we're to maintain the facade of a civil liberal democratic society, there have to be moral imperatives and moral absolutes... or so I can suggest, in theory, from the comfort of my office in the UK. I don't envy any of the people who have to deal with these things in real life.