Eric Lichtblau managed to get a few administration officials to open up—slightly—about just what kind of rulings the secret FISA court has handed down over the past decade. Among other things, there's this:
In one of the court’s most important decisions, the judges have expanded the use in terrorism cases of a legal principle known as the “special needs” doctrine and carved out an exception to the Fourth Amendment’s requirement of a warrant for searches and seizures, the officials said.
The special needs doctrine was originally established in 1989 by the Supreme Court in a ruling allowing the drug testing of railway workers, finding that a minimal intrusion on privacy was justified by the government’s need to combat an overriding public danger. Applying that concept more broadly, the FISA judges have ruled that the N.S.A.’s collection and examination of Americans’ communications data to track possible terrorists does not run afoul of the Fourth Amendment, the officials said.
Is this legit? There's no way to know because the FISA court's rulings are secret, and the presiding judge is afraid that the public might be misled if redacted versions of the rulings were released. So for now, anyway, we just have to take their word for it that all their rulings are models of statutory interpretation.