In the case of Hulbert et al. v. Twin Falls County in 1945, the U.S Supreme Court ruled on a dispute involving property tax assessments. The plaintiffs, who were non-resident owners of irrigated farm lands within an irrigation district in Idaho, claimed that their properties were assessed and taxed at a higher rate than similar properties owned by residents within the same county or district. They argued this was discriminatory and violated their rights under the Equal Protection Clause of the Fourteenth Amendment to the Constitution. However, after examining evidence presented during trial regarding assessment practices used by local authorities, including comparisons between resident-owned and non-resident-owned land values over several years, it was determined there wasn't any systematic discrimination against nonresident taxpayers as alleged by plaintiffs. Therefore, no violation of equal protection rights had occurred according to constitutional standards set forth in previous court decisions such as Sioux City Bridge v Nebraska (1923) which established that mere errors or mistakes do not constitute denial of equal protection unless they are intentional or systemic.

The dissenting opinion in the case of Hulbert et al. v. Twin Falls County argued that the majority's decision was inconsistent with previous rulings and violated principles of federalism by allowing a state to tax property owned by another state, thereby infringing upon its sovereignty. The dissenters contended that Idaho's taxation of Oregon-owned land within its borders constituted an unlawful interference with Oregon’s governmental functions, as it used this land for public purposes (specifically, reforestation). They pointed out that if every state could tax lands owned by other states within their boundaries, it would lead to chaos and conflict among states. Furthermore, they disagreed with the majority's view that there was no constitutional prohibition against such taxation; instead asserting that intergovernmental immunity from taxation is implicit in our federal system.