In the 1945 case of Mason v. Paradise Irrigation District, the United States Supreme Court dealt with a dispute over water rights in California. The plaintiff, Mason, claimed that he had been deprived of his rightful share of water from Butte Creek by the defendant, Paradise Irrigation District (PID). He argued that PID's diversion and use of this water violated his riparian rights as an upstream landowner. However, PID countered that it was entitled to use this water under its appropriative right granted by state law. The Supreme Court ruled in favor of PID. It held that while riparian owners like Mason have certain inherent rights to use adjacent waters for reasonable purposes without diminishing their quality or quantity significantly; these do not extend to prevent downstream users like PID from diverting such waters if they hold valid appropriative licenses issued under state law. This decision underscored two key principles: first, the supremacy of state laws governing allocation and usage of local natural resources; secondly - within those bounds - a balance between competing interests must be struck so as not unduly prejudice any party's legitimate expectations or needs.

The dissenting opinion in the Mason v. Paradise Irrigation District case argued that the majority's decision to uphold a California statute allowing irrigation districts to levy assessments on landowners was incorrect. The dissenters believed this law violated the Equal Protection Clause of the Fourteenth Amendment because it unfairly burdened certain property owners more than others, based solely on their location within an irrigation district. They contended that such differential treatment lacked a rational basis and thus constituted arbitrary discrimination. Furthermore, they disagreed with the majority's view that these assessments were fees for services rendered by the district rather than taxes; they saw them as taxes imposed without due process or equal protection under law.