Chancing rules in favour of incumbents
It is amusing to see claims that weakening the copyright protection of APIs is bad for free software, because if APIs had been considered copyright protected back in the 1980's, there would not be any free software implementations of operating systems. Free software started by building tools (like Emacs and GCC) running on proprietary Unix versions, and only later replaced also the operating system part with a mostly compatible implementation. In the case of BSD:s, only part of the system needed replacement, but there we had an ugly lawsuit until AT&T was forced to agree very little of the original Unix implementation remained in BSD.
Had the Unix API been considered copyrightable back then, neither Linux nor FreeBSD could exist in the present form. Probably not at all, because they would have had to implement an API that is totally different from any other OS else, and would therefore have started with a nonexistent set of applications.
Many have pointed out that Oracle's flagship product actually implements an API originally by IBM (the SQL language for issuing commands to the database). Strong API protection might have meant Oracle also would not have started. Similarly, Microsoft's first product was re-implementing DEC's flavour of the BASIC language, which arguably includes an API, I'm pretty sure they did not license it. (At the time it was actually still unclear if even code could be copyrighted - Bill Gates famously wrote an open letter pleading microcomputer to not copy his BASIC). Now that Oracle and Microsoft are established companies, they want to block the same routes they used to get started. Understandable in a way, but not something we should encourage.
The field of software already has serious a lock-in problem, which makes it hard for users with an investment in some existing platform to switch vendors and promotes monopolies. Strong protection of interfaces will make it even worse. So I fervently hope Google wins. It should also be remembered the same judgment can be used against Google, if someone wants to make a competing product that re-implements the Android API, and Google sues. If that happens, I for one will certainly root for Google's opponent!