If the evidence bar is so high, why exactly have there never been any arrests made using the data? That is an awful lot of people affected negatively for a zero benefit program. You would think a massive bureaucratic battle to only submit valid warrants would result in at least one arrest.
>why exactly have there never been any arrests made using the data?
To clarify the statements in press have been that no terrorists have been arrested based on the data. That is not the same as never having arrests.
There have been plenty of domestic arrests but they don't typically fall under the "terrorism" scope because of the nature of the act. Espionage etc... can be proven with this data and actions can be taken (like arrests) more quickly and easily than determining if someone is going to attack something a la terrorism.
A gripe I have with the community at large is that the messaging focuses too much on terrorism and not enough on the other functions that are seeing successes everyday (counterintelligence etc...).
They have been hiding the activities of FISA by using parallel construction as the basis for arrests: 1) Get dirt on someone illegaly. 2) Find a legal avenue to discover that same information now that you know it's there. That protects their collection methods when defendants try to find out how they were nabbed. The FISA warrant never has to be disclosed if no one outside the community knows it exists. Consequently they are never "officially" used for an arrest.
So the justification of the warrants is to use a "national security" cover for spying on people while evading discovery for when we don't actually use it for national security? That sounds pretty impeachable to me.