Roles are much more muddled tbetween the agencies these days. FBI is now all over the world, NSA looks at the homeland too. I don't think it's part of a conscious effort, but more from a business/prestige standpoint. IE, every group wants all their own in house capabilities, to do everything. also, I'm much more comfortable with the FBI than the NSA. FBI seems to have a more grounded approach in what the could and should be doing, whereas the NSA seems more entrepreneurial, if that makes any sense to you.