Should a company be able to shut down competition by asserting copyright in a collection of software commands? Tech giant Cisco Systems thinks so: it’s gone to court to try to prevent its competitor, Arista Networks, from building competing Ethernet switches that rely in part on commands Cisco argues it initially developed. Cisco lost the first round in a California district court, but it’s hoping for a better outcome from the Court of Appeals for the Federal Circuit.

As we explain in a brief we’ve submitted supporting Arista, Cisco is wrong. First, where the collection of commands in question is simply a group of standard, highly functional directives, arranged based on logic and industry standards, it shouldn’t be copyrightable at all. Second, any copyright that does exist must be sharply limited, as a matter of law and good practical policy. Without such limits, the software industries will find themselves embroiled in the same elaborate and expensive cross-licensing arrangements we see in the patent space and/or face an explosion of litigation. Either option will discourage innovation and competition.

So we were pleased last year when a jury found that Arista was not liable for copyright infringement based on a doctrine known as “scènes à faire.” Scènes à faire is a time-honored rule that prohibits copyright in materials that are too standard to really qualify as creative. For example, the expressive descriptions of Hogwarts—the shifting staircases, the talking paintings and so on—in J.K. Rowling’s Harry Potter books may be copyrightable, but not the idea that there would be a school for magicians. Similarly, the movie West Side Story might be copyrightable, but not the basic plot of star-crossed lovers affiliated with rival factions. Scènes à faire helps make sure that copyright can’t be used to monopolize ideas.

When it comes to computer programming and software, scènes à faire limits the ability of a copyright owner to claim copyright in basic programming elements. For example, scènes à faire prevented one company from claiming copyright infringement based on similarity between two programs’ organizational charts, as they were “simple and obvious” in light of the needs of the programs.

Here, as Arista notes in its own brief on appeal, the jury had plenty of reasons to find that any copying Arista did was noninfringing because the part copied was nothing more than what was basic and expected in the industry. We agree. Moreover, as this case shows, strong copyright defenses, including scènes à faire, are vitally important for the thriving computer software industry, innovation, and competition. The jury got it right, and set a valuable decision in the process.

That said, this case should never have gone to trial, and it wouldn’t have if the Federal Circuit hadn’t made a fundamental mistake in 2014 in a different case: Oracle v. Google.

Some background is necessary here: The Federal Circuit normally doesn’t hear copyright cases, and was only hearing the Oracle case because of a quirk in patent law. (Because of the same quirk, that court will decide Cisco v. Arista.) Since the issues in Oracle did not relate to patent law, the Federal Circuit was required to follow law from the Ninth Circuit Court of Appeals. In deciding Oracle, the court considered whether under Ninth Circuit law, the section of the Copyright Act that forbids copyright protection of ideas, processes, systems, and similar concepts meant that the Java APIs were not copyrightable. In finding that the APIs were entitled to protection, the Oracle court based its decision on the belief that the Ninth Circuit would find the APIs copyrightable, because there was more than one way to express them.

However, since the Oracle decision, the Ninth Circuit decided a case about copyright in Bikram yoga poses. In the Bikram’s Yoga case, the Ninth Circuit applied the same section of the Copyright Act as in Oracle. But unlike the Federal Circuit, the Ninth Circuit determined that a “sequence” of 26 yoga poses and two breathing exercises, performed in a particular order, was not subject to copyright protection, even though there were multiple ways to sequence the poses. And if a system of yoga poses isn’t copyrightable, then a system of APIs for operating a computer program definitely isn’t. The Federal Circuit misunderstood Ninth Circuit law, and it should use this new case as a chance to fix that mistake.

Amicus briefs in support of Arista were also submitted by Professor Pam Samuelson; Public Knowledge; CCIA (along with the American Antitrust Institute); and GitHub, Inc. (along with Mozilla Corp., Engine Advocacy, and Software Freedom Conservancy). Mathworks, SAS, Oracle, and others submitted a brief in support of Cisco.