In the case of Cardinal Chemical Company v. Morton International, Inc., 1992, the Supreme Court ruled that a federal appeals court cannot declare a patent invalid and then dismiss an appeal on grounds of mootness due to lack of controversy. The dispute began when Morton sued Cardinal for infringement on two patents related to anti-degradants used in rubber manufacturing. A district court found one patent not infringed and another invalid due to obviousness. On appeal, while affirming non-infringement verdicts, Federal Circuit also declared both patents valid but dismissed as moot Cardinal's cross-appeal seeking affirmation of lower court’s ruling about validity because it had affirmed non-infringement findings already. However, the Supreme Court reversed this decision stating that just because there was no infringement doesn't mean questions over validity are irrelevant or moot; they could still have significant legal consequences for parties involved in terms of future lawsuits or business practices.

In the dissenting opinion for Cardinal Chemical Company v. Morton International, Inc., Justice Scalia disagreed with the majority's decision to vacate and remand a lower court's ruling of patent invalidity simply because it had also found non-infringement. He argued that this approach was inconsistent with precedent and unnecessarily complicated matters by requiring two separate appeals for infringement and validity issues. Furthermore, he contended that if an appellate court finds no infringement, it should not have to address validity at all since there is no longer any case or controversy regarding the patent’s enforcement against the alleged infringer. This would save judicial resources and provide more certainty in patent litigation outcomes.