The Kentucky Union Company v. Commonwealth of Kentucky case in 1910 revolved around a dispute over taxation. The state of Kentucky had imposed taxes on the franchise and property owned by the Kentucky Union Company, which was primarily engaged in coal mining operations. The company challenged this tax imposition, arguing that it violated their rights under both federal and state constitutions because they were being taxed twice for the same property - once as real estate and again as part of its franchise value. However, the Supreme Court ruled against them stating that there was no double taxation involved since each tax targeted different aspects or values associated with their properties: one focused on physical assets while other considered business privileges granted by the state (franchise). Therefore, these two taxes did not violate any constitutional provisions related to equal protection or due process.

In the dissenting opinion for Kentucky Union Company v. Commonwealth of Kentucky, the justice argued that the majority's decision was inconsistent with previous rulings and violated principles of fairness. The justice disagreed with the court's interpretation of a state law which allowed it to tax corporations based on their property value, arguing that this unfairly targeted out-of-state companies who had no say in how these taxes were levied or spent. Furthermore, he contended that such taxation could discourage businesses from investing in states where they did not have physical presence or representation. He also took issue with what he saw as an arbitrary valuation process used by the state to determine corporate property values for tax purposes, suggesting it lacked transparency and objectivity.