It sounds a bit like Nadler confused matters.
The second link I posted above has the procedure for accessing the content of a call involving a citizen/resident;
In the third instance, the U.S. person can become a target. Here's what happens: Generally, the NSA analyst will contact a superior, who will write a report attesting to the fact that a known nuclear proliferator called a telephone number inside the U.S. This report, called an IIR, will be forwarded to the FBI's electronic communication liaison unit with NSA, and will be flagged by both the FBI and the CIA. At this point, depending upon the situation, the FBI will run with the tip, or will coordinate with the CIA, or the NSA and FBI will use the IIR to seek a FISA order to monitor the person's communications.
But the standard the court looks for is higher: Probable cause must exist to show that the U.S. person belongs to a network of proliferation. If that standard is not met, the FBI will open an investigation and determine whether indeed the person meets the standard. If he or she does, then an order will be applied for; if not, the person will be ignored — to a point. The investigative records aren't thrown away. The stored communications — remember, the NSA already captured the call — will exist in an electronic database somewhere. If ANOTHER person associated with nuclear proliferation calls the same number, the signals intelligence analyst will be able to see this immediately; remember, the NSA databases operate iteratively.
Now, to my knowledge, this is actually a bit more restrictive than the standard FISA order procedure. That's closer to what is listed for emails;
If the "score" associated with the email indicates that there is a 51 percent chance or higher that it belongs to a person overseas, the analyst can start monitoring content right away and not do anything further. If that score is less than 51 percent, the analyst can, if directed by a superior, start to access the content, if it's available, but the large team of lawyers the NSA has will be instantly notified, and a FISA order will be sought.
That is, once someone is targeted the information can immediately be accessed but must then be cleared with the court. Such orders in the case of wiretaps can be retroactive up to 72 hours. That is, you have three days from starting the tap to have it cleared. Otherwise it was an illegal search under the fourth amendment and the evidence must be destroyed.
It could be that the procedure is the minimal version, where analysis
are accessing information without warrants but getting cleared retroactively, or that the analysis can immediately access the content in the stricter standard, just knowing that the access and information may be revoked if they don't proceed with the FISC warrant.