Thank you for the correction. I clearly misremembered. It was the Federal Circuit that ruled that the API was copyrightable, not the Supreme Court: https://www.supremecourt.gov/opinions/20pdf/18-956_d18f.pdf

Yeah, but the difference is, the precedential weight of Federal Circuit decisions on copyright is about the same as the precedential weight of HN posts on copyright.

Had the case not been in the Federal Circuit because it used to have patent issues, and had the xase instead stayed in the Ninth Circuit and had that Circuit ruled that and the Supreme Court left that part of the decision untouched, there would be binding precedent, if only in the Ninth Circuit. But on issues other than its special ones (patents, in this case) the Federal Circuit is to apply precedent from the Circuit the case would otherwise be in, but does not create binding precedent.

So, other than between Oracle and Google themselves, the parties to the original case, as a matter of res judicata, the Federal Circuit decision isn't controlling on any future court the way a Supreme Court decision or even a decision of one of the geographic circuits would be.