Ars Technica has published an article highlighting a recently declassified FIS court opinion. The opinion says in a footnote that "NSA expects that it will continue to provide on average approximately three telephone identifiers per day to the FBI." Earlier opinions say NSA is providing two identifiers a day. The opinions stop putting a number on NSA's referrals in 2009. This story is accurate up to a point, but it then veers off into weirdness and paranoia:
Some experts speculated that this system of the NSA tipping off the FBI may be an unusual arrangement—analogous to the NSA’s giving information to the Drug Enforcement Agency to prosecute criminal cases. “I am not sure it tells us anything new but rather adds more confirmation to a widely suspected and occasionally confirmed technique of law enforcement following intelligence leads and then reverse-engineering a paper trail to use in court," Fred Cate, a law professor at Indiana University, told Ars. ... However, others pointed out that in the absence of further information as to how exactly the NSA’s information is sent to the FBI, and under what circumstances, it’s impossible to know precisely what’s going on. “Furthermore, given how broadly it's possible to define the word ‘tip,’ we have no information on how useful those thousand tips were,” Brian Pascal, a research fellow at the University of California Hastings College of the Law, told Ars. “Both intelligence and law enforcement organizations receive many, many tips, and a large part of their job is separating the signal from the noise. “As far as parallel construction goes, the only thing I can say for certain is that if one records a sufficiently large number of dots, then it's possible to connect them to draw any number of pictures. This is not always the result of nefarious intentions—it can happen unintentionally too. Think about all the people who were improperly placed on watchlists due to conclusions reached by some opaque algorithm.”
Huh? We don't need any of this speculation to understand why the FBI is getting tips from NSA. We just need a refresher on how the 215 program works: NSA gets a suspicious number in the US and does a link analysis to see what other numbers might be tied to that number and are themselves suspicious. If it finds a suspicious set of numbers, NSA gives them to the FBI to check out.
This means, of course, that NSA doesn't actually know even the names that are associated with the metadata it is analyzing, a fact that a fair-minded observer might be expected to know, since it's part of NSA's explanation for why the metadata program isn't "spying" on all Americans.
In fact, Ars Technica doesn't seem to realize that the FBI tips it's getting exercised about have been part of the public explanation of the 215 program for months. Despite all the hyperventilating about how NSA's search of three hops' worth of calls could lead to scrutiny of millions of subscribers, it turns out that, at its peak, the program was leading to scrutiny of maybe a thousand actual subscribers a year. I say "at its peak" because we also know that the number of tips to the Bureau has declined since 2007. By 2012, the number was down to 500 tips a year.
So, really, the headline should be "NSA cut surveillance by 50% before Snowden leaks."
But I won't hold my breath waiting for that entry to appear on Drudge.