The judge is bound by law and procedure during a court case - they can't just say "make this so" and it is so.
Judge Alsup will have authority to rule on the outcome of this case, and his judgment will stand (pending appeal), but he doesn't have the ability to say "The SSI rule is dumb, we're going to ignore it."
yes, but he is the ultimate interpretation of the law. if the law states "secret of states must be out of records" the judge is the one who decides if something is a secret of state or not, right? or can i just say that this chocolate cake recipe should be treated as so and everyone have to comply?
Only when that bit of the law is up for judicial review. This case isn't about what does and doesn't constitute SSI, and while the judge may have decided what to admit or not admit as SSI, he would have done so according to the existing rules, and would be bound by those rules to protect that information under the rules that govern the presentation of SSI in court.
Judge Alsup will have authority to rule on the outcome of this case, and his judgment will stand (pending appeal), but he doesn't have the ability to say "The SSI rule is dumb, we're going to ignore it."