The most important point is that McConnell's "fewer than 100" comment did not include all of the communications of U.S. persons that are intercepted when the surveillance is "directed at" someone overseas. Under the new law, the NSA would have the authority to intercept virtually all communications made by anyone overseas (not only suspected terrorists), as long as it could in some sense say that its surveillance was "directed at" that overseas person. This means, of course, that even if the NSA does not directly tap into every phone and computer in the U.S., the NSA could still intercept and maintain all international communications of U.S. persons, because each of those communications is, of course, with someone overseas -- and the NSA can freely intercept the latter's communications, based on no standard at all.
I would explain it this way: While there may be fewer than 100 Americans whose phones are wiretapped for intelligence purposes with a FISA court warrant, that doesn't mean there aren't thousands more whose conversations are being listened to because they happen to be talking to someone in a foreign country whose phone is tapped without a warrant. The FISA Amendment allows that and increases the likelihood it is happening.
As Marty says, it could be his conversation with a foreign scholar.
Even assuming arguendo that the new statute would not allow the NSA to tap my phone and computer without court order in order to glean information about my foreign correspondents, it remains the case that under the Act the NSA could intercept all of the communications of that foreign scholar, based on no showing at all -- indeed, could make such interceptions of the foreign scholar because it is interested in the activities of Americans with whom she deals -- and could thereafter read, maintain and use all of the communications she makes with persons here in the U.S. And this is true with respect to the communications of every single person in the world who is "reasonably believed" to be overseas.
As LNILR and I pointed out, it could be a criminal defense lawyer interviewing an overseas witness in one of our cases.
That's where minimization comes in and why it's so important. If after a short period of time, the conversation is not pertinent to the matter under investigation they must cease listening. In a Title III criminal wiretap, if the conversation is between the person being investigated and his lawyer, it's privileged and they can't listen.
More questions from Marty:
The key question is what happens when the NSA surveillance of foreigners -- possibly even vast surveillance of huge numbers of overseas communications -- invariably picks up communications that have a U.S. person at one end. Can the NSA listen to (or read) the U.S. person's communications? Can it maintain those? Can it share them with other government agencies? Make particular uses of them (i.e., for criminal investigations)? Does it have to satisfy any standards in order to do any of those things? Does it have to make any showing to a court with respect to any of those uses of U.S.-person communications? Is there congressional oversight? Does the Fourth Amendment impose any limits on such uses? Does the new statute supersede, and render inapposite, the existing internal Executive branch orders (e.g., USSID-18), which at least imposed minimal "minimization" requirements with respect to such foreign-to-domestic communications?