I think you're right. If you assume that APIs are subject to copyright, then seems clear that implementing a new system that copies only the API of another exis

I think you're right. If you assume that APIs are subject to copyright, then seems clear that implementing a new system that copies only the API of another existing system would be a violation of the copyright on the API. But it seems the judge still has to decide whether APIs are in fact copyrightable, and if he decides that they are not, then I suppose this verdict would be irrelevant.