Patent examiners have applied law to facts for as long as there has been patent examination. Written description, enablement, anticipation, obviousness, and patent-eligibility are just some of the issues that arise during examination and have legal requirements. Because examiners apply the law, practitioners often find the need to cite the law, in the form of judicial decisions, to establish patentability. Case law is particularly important for issues where statutes or rules do not fully dictate an outcome. A prime example is the issue of obviousness, where the statute is broadly written and judicial decisions have provided the more nuanced guidance that examiners apply. A timely example is patent-eligibility under 35 U.S.C. § 101, which took on added significance following Alice Corp. v. CLS Bank Int’l, 134 S. Ct. 2347 (2014). Being a judicial exception to a statute, the “abstract idea” inquiry in particular is largely driven by case law.