In the case of G.D. Searle & Co. v. Cohn et al., 1981, the U.S Supreme Court dealt with a dispute over patent rights for an intrauterine device (IUD). The respondents, Drs. Cohn and Lindemann, had developed an IUD which they claimed was unique due to its copper wire component that reduced pregnancy rates significantly more than other IUDs on the market at that time. They filed a patent application in 1969 but it wasn't until 1974 when their patent was granted after several amendments were made to their original claim. G.D Searle & Co., a pharmaceutical company who also manufactured IUDs, challenged this decision arguing that the use of copper in an IUD was not novel or non-obvious as required by law for something to be patented because there were prior art references suggesting such use before Drs.Cohn and Lindemann's filing date. The court ruled in favor of G.D Searle & Co., stating that although there may have been no explicit mention of using copper wire specifically within these previous patents or publications, one skilled in this field would find it obvious to try out different materials including metals like copper given what was known about them at that time.

In the dissenting opinion for G.D. Searle & Co. v. Cohn et al., Justice Brennan, joined by Justices Marshall and Blackmun, argued that the majority's decision to preempt state law was incorrect because it contradicted Congress' intent when passing the Medical Device Amendments of 1976 (MDA). The dissent believed that Congress intended to establish a minimum standard of safety but did not intend to prevent states from imposing stricter regulations if they chose to do so. They also pointed out that there is no explicit preemption clause in the MDA which would indicate an intention on part of Congress to supersede state laws regarding medical devices’ safety standards or liability rules. Furthermore, they disagreed with majority’s interpretation of legislative history and Congressional intent behind MDA arguing instead for a presumption against preemption unless it is clear that federal law should dominate over state law in this area.