Ben Wizner, the ACLU attorney who argued the Jeppesen case so far successfully, calls it "historic," and I think he is right. At the same time, as he points out it's not an end to anything. At most, it's the beginning -- the beginning of the civil lawsuit brought against Jeppesen by five men who were subjected to the "extraordinary rendition" and then tortured by foreign countries and Americans in Afghanistan. Jeppesen Dataplan allegedly helped to arrange the flights that transported these men to their torture countries.
A bottom-line read of the decision: the government can assert the privilege for any piece of evidence in any case. It just can't assert the privilege as an immunity doctrine -- or a justiciability doctrine -- as a way to end the case before it begins. (There are some obvious exceptions that the case today doesn't touch -- like if a spy were to sue the CIA for non-payment. Can't do that.)
But it ensures that the SSP is mostly and primarily an evidentiary privilege -- that's what civil libertarians have long wanted to hear from a court -- and that's what the State Secrets Protection Act in Congress (the formerly bipartisan Specter-Leahy SSPA) would turn into law.
"The question here is not whether there are secrets associated with this case, but whether you can determine before the case has begun whether they are absolutely indispensable for the plaintiff to the prove the case or for the defense to defend it," Wizner said.