Commil USA, LLC v. Cisco Systems, Inc.

**Question presented** Can a company that honestly thinks a patent is invalid use that belief as a defence against a claim that it *induced* other people to infringe the patent? (In other words, does “I think the patent is bad” excuse me from liability for encouraging others to copy it?) **Holding** The Supreme Court said **no**. A defendant’s belief that a patent is invalid is **not** a defence to an induced‑infringement claim. The Court’s decision was 5‑4. **How the justices voted** - Majority opinion written by Justice Kennedy, joined by Justices Ginsburg, Alito, Sotomayor, and Kagan. Justice Thomas joined the majority for Parts II‑B and III. - Justice Scalia filed a dissent, joined by Chief Justice Roberts. - Justice Breyer did not take part. **Majority’s reasoning (plain English)** 1. **Induced infringement needs knowledge of infringement** – To be liable for “inducing” infringement, a defendant must *know* that the actions it is encouraging will actually infringe a valid patent. This “knowledge” (called *scienter*) is a required element of the claim. 2. **Validity and infringement are separate questions** – Whether a patent is good or bad is a different legal issue from whether someone is copying it. The law assumes a patent is valid unless it’s successfully challenged in a separate proceeding. Letting a belief about validity replace the required knowledge of infringement would blur that line. 3. **Allowing a “belief‑in‑invalidity” defence would weaken the patent system** – If a defendant could escape liability simply by saying “I thought the patent was invalid,” it would undermine the strong presumption that patents are valid and would give parties an easy way to avoid the high burden of proving invalidity. Courts already provide proper ways to challenge a patent (e.g., re‑examination before the Patent Office), so a special defence is unnecessary and would make patent litigation more chaotic. **Dissent’s reasoning (plain English)** Justice Scalia (joined by Chief Justice Roberts) argued that the Court’s rule is too rigid. He suggested that a genuine, good‑faith belief that a patent is invalid should be taken into account, because it reflects the defendant’s state of mind and could make the “knowledge” requirement of induced infringement unfairly harsh. In his view, the statute does not expressly forbid such a defence, so the Court should not read it in. **Bottom line** – The Court clarified that, for induced‑infringement claims, the only mental‑state defence is knowledge that the acts are infringing; merely thinking a patent is invalid does not satisfy that requirement.