In the case of Valvoline Oil Co. v. United States et al., 1939, the Supreme Court was asked to determine whether or not a patent held by Valvoline for an oil refining process was valid and enforceable against alleged infringers. The lower courts had ruled in favor of the defendants, finding that the patent was invalid due to lack of novelty and non-obviousness - two key requirements for patentability under U.S law. Upon review, however, the Supreme Court reversed this decision on appeal. The court found that while similar processes did exist at the time when Valvoline's invention was patented, none were identical nor rendered it obvious; thus satisfying both criteria required for a valid patent claim: novelty and non-obviousness. Furthermore, they noted that even if some elements of an invention are known in prior art (previous patents or publicly available information), it doesn't necessarily invalidate a new combination as long as it produces new or improved results. Therefore, based on these findings and interpretations of relevant laws pertaining to patents rights protection; such as those outlined in Patent Act 35 USC §101-103 & §271(a); Justice Black delivered majority opinion ruling in favor of plaintiff - upholding validity & enforceability their contested oil refining process' patent.

The dissenting opinion in the Valvoline Oil Co. v. United States case argued that the majority's decision to uphold a tax on lubricating oil was incorrect because it violated the Export Clause of the Constitution, which prohibits taxes or duties from being imposed on exports. The dissenting justices believed that this clause should be interpreted broadly to include all stages of exportation, not just when goods are physically exported out of the country as determined by majority ruling. They contended that since Valvoline Oil Company’s product was intended for export and placed in bonded warehouses prior to actual shipment overseas, it should be considered an “export” at this stage and thus exempted from taxation under constitutional law.