In a ruling today that will cheer up patent trolls, the Supreme Court said patent owners can lie in wait for years before suing. This will allow trolls to sit around while others independently develop and build technology. The troll can then jump out from under the bridge and demand payment for work it had nothing to do with.

Today’s 7-1 decision arrives in a case called SCA Hygiene v. First Quality Baby Products. This case involves a patent on adult diapers but has a much broader reach. The court considered whether the legal doctrine of “laches” applies in patent cases. Laches is a principle that penalizes a rightsholder who “sleeps on their rights” by waiting a long time to file a lawsuit after learning of a possible infringement. It protects those that would be harmed by the assertion of rights after a lengthy delay. For example, laches would work against a patent owner that saw an infringing product emerge yet waited a decade to sue, after significant investment of time and resources had been put into the product.

The ruling in SCA follows a similar decision in Petrella v. MGM holding that laches is not available as a defense in copyright cases. The Supreme Court has generally rejected “patent exceptionalism” and has often reversed the Federal Circuit for creating special rules for patent law. So today’s decision was not especially surprising. In our view, however, there were compelling historical and policy arguments for retaining a laches defense in patent law.

Together with Public Knowledge, EFF filed an amicus brief at the Supreme Court explaining the many ways that companies accused of patent infringement can be harmed if the patent owner sleeps on its rights. For example, evidence relevant to invalidity can disappear. This is especially true for software and Internet-related patents. In his dissent, Justice Breyer cited our brief and explained:

[T]he passage of time may well harm patent defendants who wish to show a patent invalid by raising defenses of anticipation, obviousness, or insufficiency. These kinds of defenses can depend upon contemporaneous evidence that may be lost over time, and they arise far more frequently in patent cases than any of their counterparts do in copyright cases.

The seven justices in the majority suggested that patent defendants might be able to assert “equitable estoppel” instead of laches. But that would likely require showing that the patent owner somehow encouraged the defendant to infringe. In most cases, especially patent troll cases, the defendant has never even heard of the patent or the patent owner before receiving a demand. This means estoppel is unlikely to be much help. Ultimately, today’s ruling is a victory for trolls who would wait in the shadows for years before using an obscure patent to tax those who do the hard work of bringing products and services to market.