In the snoopgate scandal it's important to not get lost from the details. Not only was it egregious that the President bypassed the law to spy on Americans, but it's interesting to ponder the sort of wiretapping that was conducted. This Salon.com article, Uncle Sam is listening says the wiretapping in question was performed using the Echelon system. Now, Echelon isn't widely known about and fortunately the article describes it pretty well. Basically, we're talking about a "vacuum cleaner" approach to wiretapping.
The stereotypical wiretap has a listening post connected to a small number of individual phone circuits. It's this model which the Foreign Intelligence Surveillance Act (FISA) was meant to cover. If the spooks want to tap X's phone, they get a warrant, etc.
But todays telecommunications environment is far more complex than in the past.
The article implies that Bush turned to NSA because the FBI's wiretapping capabilities were rooted in the old model, while the NSA offered a new model. Echelon sucks in "everything", and uses pattern matching filters to extract the parts that are "important".
Most likely, Bush wanted a whole new surveillance paradigm. You can think of the FBI's capabilities as "retail surveillance": It eavesdrops on a particular person or phone. The NSA, on the other hand, conducts "wholesale surveillance." It, or more exactly its computers, listens to everything. An example might be to feed the computer a transcript of every conversation that mentions "Ayman al-Zawahiri" and monitor everybody who uttered the name, as well as everybody contacted. This type of surveillance was not anticipated in FISA and raises all sorts of legal issues. As Sen. Jay Rockefeller wrote in a secret memo after being briefed on the program, it raises "profound oversight issues," and it is unclear whether FISA would have approved this activity.
The memo by Sen. Rockefeller linked above is interesting because his mind jumps immediately to the TIA program, as does mine.
TIA, or Total Information Awareness, was a DARPA umbrella project led by former Admiral Poindexter. You may remember that Poindexter was convicted for lying to congress in the 1980's during the Iran/Contra scandal. So it's entirely fitting that he would be overseeing the creation of Big Brother. I choose the Big Brother phrase precisely because that's what TIA aimed to create.
Most of the links on my TIA page are dead (linked above) but I carefully copied over all the important points. Basically in TIA they envisioned a system which would suck in all information and filter it. It would be looking for patterns and once it found a dangerous pattern it would notify a national security agent. The "all information" would include such things as credit card transactions, cars driving through tollgates, automatic face or car license plate recognition in surveillance cameras, all communications, etc. Part of the system included automatic language translation so that they could hire whitebread americans from Texas who only know how to speak 'Merican and still have them able to analyze communications captured from any of the languages spoken by humans.
A few years ago a small part of the TIA program made it into the press, where it created a hubbub that lasted a couple weeks. The specific program had brainiacs playing a "predict the next terrorist attack" game by placing bets, and somehow this offended some professional harrrrumphers who harrumph'd until they got that program canned. The official story was TIA was killed by this, but TIA was so much more than these brainiacs playing games. And somehow the harrumphers totally missed the most consternating part of the program.
As Rockefeller says in his memo above, the idea of sucking in all the kinds of data Echelon or the larger system envisioned under TIA, well, that simply challenges the mind. As he says, how do we grasp this well enough so we can understand the oversight issues?
In the U.S. we govern through checks and balances. One branch of government oversees another branch, and checks the power held by that other branch. The goal is to keep the country from dictatorship through the branches of government holding back the power grabs by other branches of government.