In the case of Kennecott Copper Corp. v. State Tax Commission et al., 1945, the U.S Supreme Court ruled in favor of Utah's State Tax Commission. The dispute arose when Kennecott Copper Corporation challenged a tax assessment by the state on its mining properties, arguing that it was unfairly assessed and violated their rights under both federal and state law due to discriminatory taxation practices. However, the court found no evidence supporting these claims and upheld Utah’s right to levy taxes based on net proceeds from mines rather than gross yield as per its constitutionally established taxing system for mining operations within its jurisdiction.

The dissenting opinion in the Kennecott Copper Corp. v. State Tax Commission case argued that the majority's decision was inconsistent with previous rulings and principles of fair taxation. The dissent believed that Utah had unfairly taxed Kennecott by assessing its property at a higher percentage of value than other properties, violating equal protection under law as guaranteed by the Fourteenth Amendment. They contended that just because a state has power to tax does not mean it can do so arbitrarily or discriminatorily, and they felt this principle was ignored in the majority ruling. Furthermore, they disagreed with how Utah calculated Kennecott's taxable income from interstate operations; instead of using an apportionment formula based on factors like payroll and sales within the state (as is common), Utah used gross receipts derived from mining activities within its borders which resulted in disproportionate taxation compared to businesses operating solely within Utah.