In the case of Maine v. Taylor et al., 1986, the U.S. Supreme Court upheld a ban by the state of Maine on importing live baitfish. The state argued that this was necessary to protect its own fisheries from parasites and non-native species present in out-of-state baitfish populations. James A.L. Taylor, a commercial fisherman who wished to import live baitfish into Maine for resale, challenged this law as an unconstitutional violation of interstate commerce laws. The court ruled in favor of Maine with a 5-4 decision stating that while it did burden interstate trade somewhat, it served an important local purpose which could not be adequately served by available nondiscriminatory alternatives - thus making it constitutional under what is known as "the Pike balancing test". This test weighs whether benefits gained from discriminatory legislation outweighs any potential harm caused to interstate commerce. This ruling affirmed states' rights to enact conservation measures even if they might impact interstate commerce when there are no other viable options available for achieving those same conservation goals.

In the dissenting opinion for Maine v. Taylor, Justice Brennan argued that the majority's decision to uphold a ban on importing live baitfish into Maine was inconsistent with previous rulings regarding state laws affecting interstate commerce. He contended that there were non-discriminatory alternatives available to protect against potential environmental harm caused by imported fish, such as inspections and quarantines, which would not unduly burden interstate commerce. Therefore, he believed the law violated the Commerce Clause of the Constitution because it discriminated against out-of-state businesses without sufficient justification. Furthermore, he disagreed with the majority's view that local concerns outweighed national interests in this case; instead asserting that preserving a national market free from discriminatory regulations is an important federal interest.