The Busell Trimmer Company v. Stevens case in 1890 revolved around a patent dispute. The plaintiff, Busell Trimmer Company, alleged that the defendant, Stevens, had infringed on their patent for an improvement in paper trimmers - specifically those used to cut and trim books or other similar articles. However, the Supreme Court ruled against Busell Trimmer Company stating that there was no infringement as the devices were not identical nor equivalent; they operated differently and were not interchangeable in use without substantial modifications. Additionally, it was found that some of the claims made by Busell about its invention's novelty and uniqueness were unfounded since similar mechanisms existed prior to their patent application date.

The dissenting opinion in the Busell Trimmer Company v. Stevens case disagreed with the majority's decision that a patent for an improvement on a machine could be granted even if it was not novel or non-obvious. The dissent argued that granting such patents would stifle innovation and competition, as companies could simply make minor changes to existing machines and then claim exclusive rights to them. This, they believed, was contrary to the spirit of patent law which is meant to encourage new inventions rather than protect monopolies over existing ones. They also pointed out potential issues with enforcement of these types of patents due to difficulties in determining what constitutes an 'improvement'.