2022 could bring about big changes in one of the most significant and murky areas of patent law: patent eligibility. In the upcoming year, the U.S. Supreme Court will decide whether to take up a case which—in a Federal Circuit judge’s words—“bitterly divided” the appellate court on how to apply the law on patent eligibility.

The case, American Axle & Manufacturing, Inc. v. Neapco Holdings, LLC, relates to methods of manufacturing driveline propellor shafts that “attenuat[e] . . . vibrations transmitted through a shaft assembly” in order to make the shafts less noisy upon operation. A divided Federal Circuit, applying the first step of the Mayo and Alice patent eligibility test, found that claim 22 and its dependent claims were directed to a natural law (specifically Hooke’s law, addressing the force needed to express or compress a spring) because the claim “simply requires the application of Hooke’s law to tune a propshaft liner to dampen certain vibrations.” In applying step 2, the Court held that “nothing in” the method claim “qualifies as an inventive concept to transform it into patent eligible matter” because the “real inventive work lies in figuring out how to design a liner to damp two different vibration modes simultaneously, and no such inventive work is recited in” the method claim.

Interestingly, the Federal Circuit found that claim 1 was not “directed to” a natural law. Although claim 1 also covered methods of manufacturing, it included the additional step of “positioning the at least one liner.” Additionally, because the district court construed the term “tuning” in the context of claim 1 as controlling “characteristics” of at least one liner, the Federal Circuit suggested that the “characteristics” to be tuned could include variables besides those addressed by Hooke’s law, thereby potentially moving claim 1 beyond the mere application of a natural law. The Court vacated the judgment as to claim 1 and its dependent claims and remanded the case for the district court to “address this alternative eligibility theory.”

In a blistering dissent, Judge Moore called the majority’s decision “fundamentally unfair,” and stated that the majority conflated the steps of the Mayo and Alice test such that “claims are now ineligible if their performance would involve application of a natural law.” Judge Moore also accused the majority of improperly merging questions of enablement and eligibility, because the majority found that the claims “don’t teach how to tune a liner without trial and error:” according to Judge Moore, whether the patent sufficiently describes “how” to tune a liner is an issue of enablement, not eligibility.

Although the Federal Circuit is sharply divided over American Axle, they all agree that the Supreme Court should weigh in on this issue of §101. The Supreme Court appears to have taken some interest in the case: in May 2021, the Supreme Court asked the solicitor general for its consideration of American Axle’s certiorari petition, which asks the Court to reverse the Federal Circuit’s decision. Accordingly, 2022 could bring big shifts in U.S. patent eligibility law.