Patent subject matter eligibility under Section 101 of the Patent Act has proven controversial for patents in the U.S. thanks in no small part to Supreme Court jurisprudence in cases such as Alice v. CLS Bank and Mayo v. Prometheus. In the latest development, the Court has declined to hear the American Axle case, which some see as presenting an exceptionally low bar for subject matter eligibility, leaving many observers despairing of any chance of restoring a decent patent system for makers of in vitro diagnostics and other items that are among the mainstays of the medical device industry.